From: hackbard <hackbard>
Date: Fri, 27 Apr 2007 16:39:13 +0000 (+0000)
Subject: add another way of calculating tersoff + small moldyn mods
X-Git-Url: https://www.hackdaworld.org/gitweb/?p=physik%2Fposic.git;a=commitdiff_plain;h=0b96eb313c9bfec6272b1f8de0d99c4ce26d1686

add another way of calculating tersoff + small moldyn mods
---

diff --git a/Makefile b/Makefile
index 3e31459..70fcb8b 100644
--- a/Makefile
+++ b/Makefile
@@ -8,10 +8,11 @@ CFLAGS+=-g
 #CFLAGS+=-DVDEBUG
 LDFLAGS=-lm
 
-SOURCE=moldyn.c visual/visual.c random/random.c
+SOURCE=moldyn.c visual/visual.c random/random.c list/list.c
 
-POT_SRC=potentials/tersoff.c potentials/lennard_jones.c
-POT_SRC+= potentials/harmonic_oscillator.c
+POT_SRC=potentials/tersoff.c
+#POT_SRC=potentials/tersoff_orig.c
+POT_SRC+= potentials/lennard_jones.c potentials/harmonic_oscillator.c
 
 all: sic
 
diff --git a/moldyn.c b/moldyn.c
index 9a62b9f..4d73617 100644
--- a/moldyn.c
+++ b/moldyn.c
@@ -82,7 +82,7 @@ int set_pressure(t_moldyn *moldyn,double p_ref) {
 
 	moldyn->p_ref=p_ref;
 
-	printf("[moldyn] pressure [atm]: %f\n",moldyn->p_ref/ATM);
+	printf("[moldyn] pressure [bar]: %f\n",moldyn->p_ref/BAR);
 
 	return 0;
 }
@@ -176,16 +176,37 @@ int set_potential2b(t_moldyn *moldyn,pf_func2b func) {
 	return 0;
 }
 
-int set_potential2b_post(t_moldyn *moldyn,pf_func2b_post func) {
+int set_potential3b_j1(t_moldyn *moldyn,pf_func2b func) {
 
-	moldyn->func2b_post=func;
+	moldyn->func3b_j1=func;
 
 	return 0;
 }
 
-int set_potential3b(t_moldyn *moldyn,pf_func3b func) {
+int set_potential3b_j2(t_moldyn *moldyn,pf_func2b func) {
 
-	moldyn->func3b=func;
+	moldyn->func3b_j2=func;
+
+	return 0;
+}
+
+int set_potential3b_j3(t_moldyn *moldyn,pf_func2b func) {
+
+	moldyn->func3b_j3=func;
+
+	return 0;
+}
+
+int set_potential3b_k1(t_moldyn *moldyn,pf_func3b func) {
+
+	moldyn->func3b_k1=func;
+
+	return 0;
+}
+
+int set_potential3b_k2(t_moldyn *moldyn,pf_func3b func) {
+
+	moldyn->func3b_k2=func;
 
 	return 0;
 }
@@ -294,6 +315,7 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,int timer) {
 				perror("[moldyn] report fd open");	
 				return moldyn->rfd;
 			}
+			printf("report -> ");
 			if(moldyn->efd) {
 				snprintf(filename,127,"%s/e_plot.scr",
 				         moldyn->vlsdir);
@@ -306,6 +328,7 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,int timer) {
 				}
 				dprintf(moldyn->epfd,e_plot_script);
 				close(moldyn->epfd);
+				printf("energy ");
 			}
 			if(moldyn->pfd) {
 				snprintf(filename,127,"%s/pressure_plot.scr",
@@ -319,6 +342,7 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,int timer) {
 				}
 				dprintf(moldyn->ppfd,pressure_plot_script);
 				close(moldyn->ppfd);
+				printf("pressure ");
 			}
 			if(moldyn->tfd) {
 				snprintf(filename,127,"%s/temperature_plot.scr",
@@ -332,9 +356,11 @@ int moldyn_set_log(t_moldyn *moldyn,u8 type,int timer) {
 				}
 				dprintf(moldyn->tpfd,temperature_plot_script);
 				close(moldyn->tpfd);
+				printf("temperature ");
 			}
 			dprintf(moldyn->rfd,report_start,
 			        moldyn->rauthor,moldyn->rtitle);
+			printf("\n");
 			break;
 		default:
 			printf("unknown log type: %02x\n",type);
@@ -672,6 +698,8 @@ double temperature_calc(t_moldyn *moldyn) {
 	/* assume up to date kinetic energy, which is 3/2 N k_B T */
 
 	moldyn->t=(2.0*moldyn->ekin)/(3.0*K_BOLTZMANN*moldyn->count);
+	moldyn->t_sum+=moldyn->t;
+	moldyn->mean_t=moldyn->t_sum/moldyn->total_steps;
 
 	return moldyn->t;
 }
@@ -769,6 +797,16 @@ double pressure_calc(t_moldyn *moldyn) {
 	/* assume up to date kinetic energy */
 	moldyn->p=2.0*moldyn->ekin+v;
 	moldyn->p/=(3.0*moldyn->volume);
+	moldyn->p_sum+=moldyn->p;
+	moldyn->mean_p=moldyn->p_sum/moldyn->total_steps;
+
+	/* pressure from 'absolute coordinates' virial */
+	virial=&(moldyn->virial);
+	v=virial->xx+virial->yy+virial->zz;
+	moldyn->gp=2.0*moldyn->ekin+v;
+	moldyn->gp/=(3.0*moldyn->volume);
+	moldyn->gp_sum+=moldyn->gp;
+	moldyn->mean_gp=moldyn->gp_sum/moldyn->total_steps;
 
 	return moldyn->p;
 }	
@@ -788,7 +826,7 @@ double thermodynamic_pressure_calc(t_moldyn *moldyn) {
 	 * dV: dx,y,z = 0.001 x,y,z
 	 */
 
-	scale=1.00001;
+	scale=1.00000000000001;
 printf("\n\nP-DEBUG:\n");
 
 	tp=&(moldyn->tp);
@@ -806,13 +844,12 @@ printf("\n\nP-DEBUG:\n");
 	/* derivative with respect to x direction */
 	scale_dim(moldyn,scale,TRUE,0,0);
 	scale_atoms(moldyn,scale,TRUE,0,0);
-	dv=0.00001*moldyn->dim.x*moldyn->dim.y*moldyn->dim.z;
+	dv=0.00000000000001*moldyn->dim.x*moldyn->dim.y*moldyn->dim.z;
 	link_cell_shutdown(moldyn);
 	link_cell_init(moldyn,QUIET);
 	potential_force_calc(moldyn);
 	tp->x=(moldyn->energy-u)/dv;
 	p=tp->x*tp->x;
-printf("e: %f eV de: %f eV dV: %f A^3\n",moldyn->energy/moldyn->count/EV,(moldyn->energy-u)/moldyn->count/EV,dv);
 
 	/* restore atomic configuration + dim */
 	memcpy(moldyn->atom,store,moldyn->count*sizeof(t_atom));
@@ -821,7 +858,7 @@ printf("e: %f eV de: %f eV dV: %f A^3\n",moldyn->energy/moldyn->count/EV,(moldyn
 	/* derivative with respect to y direction */
 	scale_dim(moldyn,scale,0,TRUE,0);
 	scale_atoms(moldyn,scale,0,TRUE,0);
-	dv=0.00001*moldyn->dim.y*moldyn->dim.x*moldyn->dim.z;
+	dv=0.00000000000001*moldyn->dim.y*moldyn->dim.x*moldyn->dim.z;
 	link_cell_shutdown(moldyn);
 	link_cell_init(moldyn,QUIET);
 	potential_force_calc(moldyn);
@@ -835,7 +872,7 @@ printf("e: %f eV de: %f eV dV: %f A^3\n",moldyn->energy/moldyn->count/EV,(moldyn
 	/* derivative with respect to z direction */
 	scale_dim(moldyn,scale,0,0,TRUE);
 	scale_atoms(moldyn,scale,0,0,TRUE);
-	dv=0.00001*moldyn->dim.z*moldyn->dim.x*moldyn->dim.y;
+	dv=0.00000000000001*moldyn->dim.z*moldyn->dim.x*moldyn->dim.y;
 	link_cell_shutdown(moldyn);
 	link_cell_init(moldyn,QUIET);
 	potential_force_calc(moldyn);
@@ -939,7 +976,7 @@ moldyn->debug=scale;
 
 }
 
-double get_e_kin(t_moldyn *moldyn) {
+double e_kin_calc(t_moldyn *moldyn) {
 
 	int i;
 	t_atom *atom;
@@ -953,11 +990,6 @@ double get_e_kin(t_moldyn *moldyn) {
 	return moldyn->ekin;
 }
 
-double update_e_kin(t_moldyn *moldyn) {
-
-	return(get_e_kin(moldyn));
-}
-
 double get_total_energy(t_moldyn *moldyn) {
 
 	return(moldyn->ekin+moldyn->energy);
@@ -1018,7 +1050,12 @@ int link_cell_init(t_moldyn *moldyn,u8 vol) {
 	if(lc->cells<27)
 		printf("[moldyn] FATAL: less then 27 subcells!\n");
 
-	if(vol) printf("[moldyn] initializing linked cells (%d)\n",lc->cells);
+	if(vol) {
+		printf("[moldyn] initializing linked cells (%d)\n",lc->cells);
+		printf("  x: %d x %f A\n",lc->nx,lc->x);
+		printf("  y: %d x %f A\n",lc->ny,lc->y);
+		printf("  z: %d x %f A\n",lc->nz,lc->z);
+	}
 
 	for(i=0;i<lc->cells;i++)
 		list_init_f(&(lc->subcell[i]));
@@ -1053,7 +1090,7 @@ int link_cell_update(t_moldyn *moldyn) {
 		i=((atom[count].r.x+(moldyn->dim.x/2))/lc->x);
 		j=((atom[count].r.y+(moldyn->dim.y/2))/lc->y);
 		k=((atom[count].r.z+(moldyn->dim.z/2))/lc->z);
-		list_add_immediate_f(&(moldyn->lc.subcell[i+j*nx+k*nx*ny]),
+		list_add_immediate_f(&(lc->subcell[i+j*nx+k*nx*ny]),
 		                     &(atom[count]));
 	}
 
@@ -1229,6 +1266,7 @@ int moldyn_integrate(t_moldyn *moldyn) {
 
 	/* zero absolute time */
 	moldyn->time=0.0;
+	moldyn->total_steps=0;
 
 	/* debugging, ignore */
 	moldyn->debug=0;
@@ -1252,10 +1290,11 @@ int moldyn_integrate(t_moldyn *moldyn) {
 		moldyn->integrate(moldyn);
 
 		/* calculate kinetic energy, temperature and pressure */
-		update_e_kin(moldyn);
+		e_kin_calc(moldyn);
 		temperature_calc(moldyn);
 		pressure_calc(moldyn);
 		//tp=thermodynamic_pressure_calc(moldyn);
+//printf("thermodynamic p: %f %f %f - %f\n",moldyn->tp.x/BAR,moldyn->tp.y/BAR,moldyn->tp.z/BAR,tp/BAR);
 
 		/* p/t scaling */
 		if(moldyn->pt_scale&(T_SCALE_BERENDSEN|T_SCALE_DIRECT))
@@ -1284,13 +1323,16 @@ int moldyn_integrate(t_moldyn *moldyn) {
 		if(p) {
 			if(!(i%p)) {
 				dprintf(moldyn->pfd,
-				        "%f %f\n",moldyn->time,moldyn->p/ATM);
+				        "%f %f %f %f %f\n",moldyn->time,
+				         moldyn->p/BAR,moldyn->mean_p/BAR,
+				         moldyn->gp/BAR,moldyn->mean_gp/BAR);
 			}
 		}
 		if(t) {
 			if(!(i%t)) {
 				dprintf(moldyn->tfd,
-				        "%f %f\n",moldyn->time,moldyn->t);
+				        "%f %f %f\n",
+				        moldyn->time,moldyn->t,moldyn->mean_t);
 			}
 		}
 		if(s) {
@@ -1316,14 +1358,18 @@ int moldyn_integrate(t_moldyn *moldyn) {
 
 		/* display progress */
 		if(!(i%10)) {
-			printf("\rsched: %d, steps: %d, T: %f, P: %f V: %f",
+			printf("\rsched: %d, steps: %d, T: %f, P: %f %f V: %f",
 			       sched->count,i,
-			       moldyn->t,moldyn->p/ATM,moldyn->volume);
+			       moldyn->mean_t,
+			       moldyn->mean_p/BAR,
+			       moldyn->mean_gp/BAR,
+			       moldyn->volume);
 			fflush(stdout);
 		}
 
 		/* increase absolute time */
 		moldyn->time+=moldyn->tau;
+		moldyn->total_steps+=1;
 
 	}
 
@@ -1410,6 +1456,9 @@ int potential_force_calc(t_moldyn *moldyn) {
 	/* reset energy */
 	moldyn->energy=0.0;
 
+	/* reset global virial */
+	memset(&(moldyn->virial),0,sizeof(t_virial));
+
 	/* reset force, site energy and virial of every atom */
 	for(i=0;i<count;i++) {
 
@@ -1430,7 +1479,9 @@ int potential_force_calc(t_moldyn *moldyn) {
 
 	}
 
-	/* get energy,force and virial of every atom */
+	/* get energy, force and virial of every atom */
+
+	/* first (and only) loop over atoms i */
 	for(i=0;i<count;i++) {
 
 		/* single particle potential/force */
@@ -1450,6 +1501,45 @@ int potential_force_calc(t_moldyn *moldyn) {
 
 		dnlc=lc->dnlc;
 
+		/* first loop over atoms j */
+		if(moldyn->func2b) {
+			for(j=0;j<27;j++) {
+
+				this=&(neighbour_i[j]);
+				list_reset_f(this);
+
+				if(this->start==NULL)
+					continue;
+
+				bc_ij=(j<dnlc)?0:1;
+
+				do {
+					jtom=this->current->data;
+
+					if(jtom==&(itom[i]))
+						continue;
+
+					if((jtom->attr&ATOM_ATTR_2BP)&
+					   (itom[i].attr&ATOM_ATTR_2BP)) {
+						moldyn->func2b(moldyn,
+						               &(itom[i]),
+						               jtom,
+					        	       bc_ij);
+					}
+				} while(list_next_f(this)!=L_NO_NEXT_ELEMENT);
+
+			}
+		}
+
+		/* 3 body potential/force */
+
+		if(!(itom[i].attr&ATOM_ATTR_3BP))
+			continue;
+
+		/* copy the neighbour lists */
+		memcpy(neighbour_i2,neighbour_i,27*sizeof(t_list));
+
+		/* second loop over atoms j */
 		for(j=0;j<27;j++) {
 
 			this=&(neighbour_i[j]);
@@ -1466,25 +1556,70 @@ int potential_force_calc(t_moldyn *moldyn) {
 				if(jtom==&(itom[i]))
 					continue;
 
-				if((jtom->attr&ATOM_ATTR_2BP)&
-				   (itom[i].attr&ATOM_ATTR_2BP)) {
-					moldyn->func2b(moldyn,
-					               &(itom[i]),
-					               jtom,
-					               bc_ij);
-				}
+				if(!(jtom->attr&ATOM_ATTR_3BP))
+					continue;
 
-				/* 3 body potential/force */
+				/* reset 3bp run */
+				moldyn->run3bp=1;
 
-				if(!(itom[i].attr&ATOM_ATTR_3BP)||
-				   !(jtom->attr&ATOM_ATTR_3BP))
+				if(moldyn->func3b_j1)
+					moldyn->func3b_j1(moldyn,
+					                  &(itom[i]),
+					                  jtom,
+					                  bc_ij);
+
+				/* in first j loop, 3bp run can be skipped */
+				if(!(moldyn->run3bp))
 					continue;
+			
+				/* first loop over atoms k */
+				if(moldyn->func3b_k1) {
+
+				for(k=0;k<27;k++) {
+
+					that=&(neighbour_i2[k]);
+					list_reset_f(that);
+					
+					if(that->start==NULL)
+						continue;
+
+					bc_ik=(k<dnlc)?0:1;
 
-				/* copy the neighbour lists */
-				memcpy(neighbour_i2,neighbour_i,
-				       27*sizeof(t_list));
+					do {
+
+						ktom=that->current->data;
+
+						if(!(ktom->attr&ATOM_ATTR_3BP))
+							continue;
+
+						if(ktom==jtom)
+							continue;
+
+						if(ktom==&(itom[i]))
+							continue;
+
+						moldyn->func3b_k1(moldyn,
+						                  &(itom[i]),
+						                  jtom,
+						                  ktom,
+						                  bc_ik|bc_ij);
+
+					} while(list_next_f(that)!=\
+					        L_NO_NEXT_ELEMENT);
+
+				}
+
+				}
+
+				if(moldyn->func3b_j2)
+					moldyn->func3b_j2(moldyn,
+					                  &(itom[i]),
+					                  jtom,
+					                  bc_ij);
+
+				/* second loop over atoms k */
+				if(moldyn->func3b_k2) {
 
-				/* get neighbours of i */
 				for(k=0;k<27;k++) {
 
 					that=&(neighbour_i2[k]);
@@ -1508,37 +1643,53 @@ int potential_force_calc(t_moldyn *moldyn) {
 						if(ktom==&(itom[i]))
 							continue;
 
-						moldyn->func3b(moldyn,
-						               &(itom[i]),
-						               jtom,
-						               ktom,
-						               bc_ik|bc_ij);
+						moldyn->func3b_k2(moldyn,
+						                  &(itom[i]),
+						                  jtom,
+						                  ktom,
+						                  bc_ik|bc_ij);
 
 					} while(list_next_f(that)!=\
 					        L_NO_NEXT_ELEMENT);
 
 				}
+				
+				}
 
 				/* 2bp post function */
-				if(moldyn->func2b_post) {
-					moldyn->func2b_post(moldyn,
-					                    &(itom[i]),
-					                    jtom,bc_ij);
+				if(moldyn->func3b_j3) {
+					moldyn->func3b_j3(moldyn,
+					                  &(itom[i]),
+					                  jtom,bc_ij);
 				}
 					
 			} while(list_next_f(this)!=L_NO_NEXT_ELEMENT);
 		
 		}
+		
+#ifdef DEBUG
+	//printf("\n\n");
+#endif
+#ifdef VDEBUG
+	printf("\n\n");
+#endif
 
 	}
 
 #ifdef DEBUG
-printf("\n\n");
-#endif
-#ifdef VDEBUG
-printf("\n\n");
+	printf("\nATOM 0: %f %f %f\n\n",itom->f.x,itom->f.y,itom->f.z);
 #endif
 
+	/* calculate global virial */
+	for(i=0;i<count;i++) {
+		moldyn->virial.xx+=moldyn->atom[i].r.x*moldyn->atom[i].f.x;
+		moldyn->virial.yy+=moldyn->atom[i].r.y*moldyn->atom[i].f.y;
+		moldyn->virial.zz+=moldyn->atom[i].r.z*moldyn->atom[i].f.z;
+		moldyn->virial.xy+=moldyn->atom[i].r.y*moldyn->atom[i].f.x;
+		moldyn->virial.xz+=moldyn->atom[i].r.z*moldyn->atom[i].f.x;
+		moldyn->virial.yz+=moldyn->atom[i].r.z*moldyn->atom[i].f.y;
+	}
+
 	return 0;
 }
 
diff --git a/moldyn.h b/moldyn.h
index 85a4950..5b12048 100644
--- a/moldyn.h
+++ b/moldyn.h
@@ -85,11 +85,15 @@ typedef struct s_moldyn {
 	/* potential force function and parameter pointers */
 	int (*func1b)(struct s_moldyn *moldyn,t_atom *ai);
 	int (*func2b)(struct s_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
-	int (*func2b_post)(struct s_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
-	int (*func3b)(struct s_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,
-	              u8 bck);
+	int (*func3b_j1)(struct s_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
+	int (*func3b_j2)(struct s_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
+	int (*func3b_j3)(struct s_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
+	int (*func3b_k1)(struct s_moldyn *moldyn,
+	                 t_atom *ai,t_atom *aj,t_atom *ak,u8 bck);
+	int (*func3b_k2)(struct s_moldyn *moldyn,
+	                 t_atom *ai,t_atom *aj,t_atom *ak,u8 bck);
 	void *pot_params;
-	//int (*potential_force_function)(struct s_moldyn *moldyn);
+	unsigned char run3bp;
 
 	double cutoff;		/* cutoff radius */
 	double cutoff_square;	/* square of the cutoff radius */
@@ -99,9 +103,18 @@ typedef struct s_moldyn {
 
 	double t_ref;		/* reference temperature */
 	double t;		/* actual temperature */
+	double t_sum;		/* sum over all t */
+	double mean_t;		/* mean value of t */
+
+	t_virial virial;	/* global virial (absolute coordinates) */
+	double gp;		/* pressure computed from global virial */
+	double gp_sum;		/* sum over all gp */
+	double mean_gp;		/* mean value of gp */
 
 	double p_ref;		/* reference pressure */
 	double p;		/* actual pressure (computed by virial) */
+	double p_sum;		/* sum over all p */
+	double mean_p;		/* mean value of p */
 	t_3dvec tp;		/* thermodynamic pressure dU/dV */
 	double dv;		/* dV for thermodynamic pressure calc */
 
@@ -121,7 +134,7 @@ typedef struct s_moldyn {
 	double tau;		/* delta t */
 	double time;		/* absolute time */
 	double tau_square;	/* delta t squared */
-	double elapsed;		/* total elapsed time */
+	int total_steps;	/* total steps */
 
 	double energy;		/* potential energy */
 	double ekin;		/* kinetic energy */
@@ -175,7 +188,7 @@ typedef struct s_moldyn {
 #define P_SCALE_DIRECT			0x08	/* direct p control */
 
 /*
- * default values
+ * default values & units
  *
  * - length unit: 1 A (1 A = 1e-10 m)
  * - time unit: 1 fs (1 fs = 1e-15 s)
@@ -191,7 +204,9 @@ typedef struct s_moldyn {
 #define KILOGRAM			(1.0/AMU)		/* amu */
 #define NEWTON	(METER*KILOGRAM/(SECOND*SECOND))	/* A amu / fs^2 */
 #define PASCAL	(NEWTON/(METER*METER))			/* N / A^2 */
-#define ATM	((1.0133e5*PASCAL))			/* N / A^2 */
+#define BAR	((1.0e5*PASCAL))			/* N / A^2 */
+#define K_BOLTZMANN	(1.380650524e-23*METER*NEWTON)	/* NA/K */
+#define EV		(1.6021765314e-19*METER*NEWTON)	/* NA */
 
 #define MOLDYN_TEMP			273.0
 #define MOLDYN_TAU			1.0
@@ -220,17 +235,12 @@ typedef struct s_moldyn {
 #define QUIET				0
 
 /*
- *
- * phsical values / constants
- *
+ * potential related phsical values / constants
  *
  */
 
 #define ONE_THIRD		(1.0/3.0)
 
-#define K_BOLTZMANN		(1.380650524e-23*METER*NEWTON)	/* NA/K */
-#define EV			(1.6021765314e-19*METER*NEWTON)	/* NA */
-
 #define C			0x06
 #define M_C			12.011				/* amu */
 
@@ -284,10 +294,9 @@ typedef struct s_moldyn {
  *
  */
 
-typedef int (*pf_func1b)(t_moldyn *,t_atom *ai);
-typedef int (*pf_func2b)(t_moldyn *,t_atom *,t_atom *,u8 bc);
-typedef int (*pf_func2b_post)(t_moldyn *,t_atom *,t_atom *,u8 bc);
-typedef int (*pf_func3b)(t_moldyn *,t_atom *,t_atom *,t_atom *,u8 bc);
+typedef int (*pf_func1b)(t_moldyn *,t_atom *);
+typedef int (*pf_func2b)(t_moldyn *,t_atom *,t_atom *,u8);
+typedef int (*pf_func3b)(t_moldyn *,t_atom *,t_atom *,t_atom *,u8);
 
 int moldyn_init(t_moldyn *moldyn,int argc,char **argv);
 int moldyn_shutdown(t_moldyn *moldyn);
@@ -302,8 +311,11 @@ int set_nn_dist(t_moldyn *moldyn,double dist);
 int set_pbc(t_moldyn *moldyn,u8 x,u8 y,u8 z);
 int set_potential1b(t_moldyn *moldyn,pf_func1b func);
 int set_potential2b(t_moldyn *moldyn,pf_func2b func);
-int set_potential2b_post(t_moldyn *moldyn,pf_func2b_post func);
-int set_potential3b(t_moldyn *moldyn,pf_func3b func);
+int set_potential3b_j1(t_moldyn *moldyn,pf_func2b func);
+int set_potential3b_j2(t_moldyn *moldyn,pf_func2b func);
+int set_potential3b_j3(t_moldyn *moldyn,pf_func2b func);
+int set_potential3b_k1(t_moldyn *moldyn,pf_func3b func);
+int set_potential3b_k2(t_moldyn *moldyn,pf_func3b func);
 int set_potential_params(t_moldyn *moldyn,void *params);
 
 int moldyn_set_log_dir(t_moldyn *moldyn,char *dir);
@@ -331,8 +343,7 @@ int scale_volume(t_moldyn *moldyn);
 int scale_dim(t_moldyn *moldyn,double scale,u8 x,u8 y,u8 z);
 int scale_atoms(t_moldyn *moldyn,double scale,u8 x,u8 y,u8 z);
 
-double get_e_kin(t_moldyn *moldyn);
-double update_e_kin(t_moldyn *moldyn);
+double e_kin_calc(t_moldyn *moldyn);
 double get_total_energy(t_moldyn *moldyn);
 t_3dvec get_total_p(t_moldyn *moldyn);
 
diff --git a/potentials/tersoff.c b/potentials/tersoff.c
index 16f771c..531d292 100644
--- a/potentials/tersoff.c
+++ b/potentials/tersoff.c
@@ -85,10 +85,9 @@ int tersoff_mult_1bp(t_moldyn *moldyn,t_atom *ai) {
 int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 
 	t_tersoff_mult_params *params;
-	t_tersoff_exchange *exchange;
 	t_3dvec dist_ij,force;
 	double d_ij,d_ij2;
-	double A,B,R,S,S2,lambda,mu;
+	double A,R,S,S2,lambda;
 	double f_r,df_r;
 	double f_c,df_c;
 	int brand;
@@ -96,31 +95,10 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 	double arg;
 
 	/* use newtons third law */
-	//if(ai<aj) return 0;
+	if(ai<aj) return 0;
 
 	params=moldyn->pot_params;
 	brand=aj->brand;
-	exchange=&(params->exchange);
-
-	/* clear 3bp and 2bp post run */
-	exchange->run3bp=0;
-	exchange->run2bp_post=0;
-
-	/* reset S > r > R mark */
-	exchange->d_ij_between_rs=0;
-	
-	/*
-	 * calc of 2bp contribution of V_ij and dV_ij/ji
-	 *
-	 * for Vij and dV_ij we need:
-	 * - f_c_ij, df_c_ij
-	 * - f_r_ij, df_r_ij
-	 *
-	 * for dV_ji we need:
-	 * - f_c_ji = f_c_ij, df_c_ji = df_c_ij
-	 * - f_r_ji = f_r_ij; df_r_ji = df_r_ij
-	 *
-	 */
 
 	/* determine cutoff square */
 	if(brand==ai->brand)
@@ -128,71 +106,41 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 	else
 		S2=params->S2mixed;
 
-	/* dist_ij, d_ij */
+	/* dist_ij, d_ij2 */
 	v3_sub(&dist_ij,&(aj->r),&(ai->r));
 	if(bc) check_per_bound(moldyn,&dist_ij);
 	d_ij2=v3_absolute_square(&dist_ij);
 
 	/* if d_ij2 > S2 => no force & potential energy contribution */
-	if(d_ij2>S2)
+	if(d_ij2>S2) {
 		return 0;
+	}
 
 	/* now we will need the distance */
-	//d_ij=v3_norm(&dist_ij);
 	d_ij=sqrt(d_ij2);
 
-	/* save for use in 3bp */
-	exchange->d_ij=d_ij;
-	exchange->d_ij2=d_ij2;
-	exchange->dist_ij=dist_ij;
-
 	/* more constants */
-	exchange->beta_j=&(params->beta[brand]);
-	exchange->n_j=&(params->n[brand]);
-	exchange->c_j=&(params->c[brand]);
-	exchange->d_j=&(params->d[brand]);
-	exchange->h_j=&(params->h[brand]);
 	if(brand==ai->brand) {
 		S=params->S[brand];
 		R=params->R[brand];
 		A=params->A[brand];
-		B=params->B[brand];
 		lambda=params->lambda[brand];
-		mu=params->mu[brand];
-		exchange->chi=1.0;
-		exchange->betajnj=exchange->betaini;
-		exchange->cj2=exchange->ci2;
-		exchange->dj2=exchange->di2;
-		exchange->cj2dj2=exchange->ci2di2;
 	}
 	else {
 		S=params->Smixed;
 		R=params->Rmixed;
 		A=params->Amixed;
-		B=params->Bmixed;
 		lambda=params->lambda_m;
-		mu=params->mu_m;
-		params->exchange.chi=params->chi;
-		exchange->betajnj=pow(*(exchange->beta_j),*(exchange->n_j));
-		exchange->cj2=params->c[brand]*params->c[brand];
-		exchange->dj2=params->d[brand]*params->d[brand];
-		exchange->cj2dj2=exchange->cj2/exchange->dj2;
 	}
 
-	/* f_r_ij = f_r_ji, df_r_ij = df_r_ji */
+	/* f_r_ij, df_r_ij */
 	f_r=A*exp(-lambda*d_ij);
 	df_r=lambda*f_r/d_ij;
 
-	/* f_a, df_a calc (again, same for ij and ji) | save for later use! */
-	exchange->f_a=-B*exp(-mu*d_ij);
-	exchange->df_a=mu*exchange->f_a/d_ij;
-
-	/* f_c, df_c calc (again, same for ij and ji) */
+	/* f_c, df_c */
 	if(d_ij<R) {
-		/* f_c = 1, df_c = 0 */
 		f_c=1.0;
 		df_c=0.0;
-		/* two body contribution (ij, ji) */
 		v3_scale(&force,&dist_ij,-df_r);
 	}
 	else {
@@ -200,18 +148,27 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 		arg=M_PI*(d_ij-R)/s_r;
 		f_c=0.5+0.5*cos(arg);
 		df_c=0.5*sin(arg)*(M_PI/(s_r*d_ij));
-		/* two body contribution (ij, ji) */
 		v3_scale(&force,&dist_ij,-df_c*f_r-df_r*f_c);
-		/* tell 3bp that S > r > R */
-		exchange->d_ij_between_rs=1;
 	}
 
-	/* add forces of 2bp (ij, ji) contribution
-	 * dVij = dVji and we sum up both: no 1/2) */
+	/* add forces */
 	v3_add(&(ai->f),&(ai->f),&force);
+	v3_sub(&(aj->f),&(aj->f),&force);
+
+#ifdef DEBUG
+	if((ai==&(moldyn->atom[0]))|(aj==&(moldyn->atom[0]))) {
+		printf("force 2bp: [%d %d]\n",ai->tag,aj->tag);
+		printf("adding %f %f %f\n",force.x,force.y,force.z);
+		if(ai==&(moldyn->atom[0]))
+			printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
+		if(aj==&(moldyn->atom[0]))
+			printf("total j: %f %f %f\n",aj->f.x,aj->f.y,aj->f.z);
+	}
+#endif
 
 	/* virial */
-	virial_calc(ai,&force,&dist_ij);
+	//virial_calc(ai,&force,&dist_ij);
+	//virial_calc(aj,&force,&dist_ij);
 	//ai->virial.xx-=force.x*dist_ij.x;
 	//ai->virial.yy-=force.y*dist_ij.y;
 	//ai->virial.zz-=force.z*dist_ij.z;
@@ -219,270 +176,86 @@ int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 	//ai->virial.xz-=force.x*dist_ij.z;
 	//ai->virial.yz-=force.y*dist_ij.z;
 
-#ifdef DEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVij, dVji (2bp) contrib:\n");
-	printf("%f | %f\n",force.x,ai->f.x);
-	printf("%f | %f\n",force.y,ai->f.y);
-	printf("%f | %f\n",force.z,ai->f.z);
-}
-#endif
-#ifdef VDEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVij, dVji (2bp) contrib:\n");
-	printf("%f | %f\n",force.x*dist_ij.x,ai->virial.xx);
-	printf("%f | %f\n",force.y*dist_ij.y,ai->virial.yy);
-	printf("%f | %f\n",force.z*dist_ij.z,ai->virial.zz);
-}
-#endif
-
-	/* energy 2bp contribution (ij, ji) is 0.5 f_r f_c ... */
-	moldyn->energy+=(0.5*f_r*f_c);
-
-	/* save for use in 3bp */
-	exchange->f_c=f_c;
-	exchange->df_c=df_c;
-
-	/* enable the run of 3bp function and 2bp post processing */
-	exchange->run3bp=1;
-	exchange->run2bp_post=1;
-
-	/* reset 3bp sums */
-	exchange->zeta_ij=0.0;
-	exchange->zeta_ji=0.0;
-	v3_zero(&(exchange->dzeta_ij));
-	v3_zero(&(exchange->dzeta_ji));
+	/* energy 2bp contribution */
+	moldyn->energy+=f_r*f_c;
 
 	return 0;
 }
 
-/* tersoff 2 body post part */
-
-int tersoff_mult_post_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
-
-	/*
-	 * here we have to allow for the 3bp sums
-	 *
-	 * that is:
-	 * - zeta_ij, dzeta_ij
-	 * - zeta_ji, dzeta_ji
-	 *
-	 * to compute the 3bp contribution to:
-	 * - Vij, dVij
-	 * - dVji
-	 *
-	 */
+/* tersoff 3 body potential function (first ij loop) */
+int tersoff_mult_3bp_j1(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
 
 	t_tersoff_mult_params *params;
 	t_tersoff_exchange *exchange;
-
-	t_3dvec force,temp;
-	t_3dvec *dist_ij;
-	double b,db,tmp;
-	double f_c,df_c,f_a,df_a;
-	double chi,ni,betaini,nj,betajnj;
-	double zeta;
+	unsigned char brand;
+	double S2;
+	t_3dvec dist_ij;
+	double d_ij2,d_ij;
 
 	params=moldyn->pot_params;
 	exchange=&(params->exchange);
 
-	/* we do not run if f_c_ij was detected to be 0! */
-	if(!(exchange->run2bp_post))
-		return 0;
-
-	f_c=exchange->f_c;
-	df_c=exchange->df_c;
-	f_a=exchange->f_a;
-	df_a=exchange->df_a;
-	betaini=exchange->betaini;
-	betajnj=exchange->betajnj;
-	ni=*(exchange->n_i);
-	nj=*(exchange->n_j);
-	chi=exchange->chi;
-	dist_ij=&(exchange->dist_ij);
-	
-	/* Vij and dVij */
-	zeta=exchange->zeta_ij;
-	if(zeta==0.0) {
-		moldyn->debug++;		/* just for debugging ... */
-		b=chi;
-		v3_scale(&force,dist_ij,df_a*b*f_c);
-	}
-	else {
-		tmp=betaini*pow(zeta,ni-1.0);		/* beta^n * zeta^n-1 */
-		b=(1+zeta*tmp);				/* 1 + beta^n zeta^n */
-		db=chi*pow(b,-1.0/(2*ni)-1);		/* x(...)^(-1/2n - 1) */
-		b=db*b;					/* b_ij */
-		db*=-0.5*tmp;				/* db_ij */
-		v3_scale(&force,&(exchange->dzeta_ij),f_a*db);
-		v3_scale(&temp,dist_ij,df_a*b);
-		v3_add(&force,&force,&temp);
-		v3_scale(&force,&force,f_c);
-	}
-	v3_scale(&temp,dist_ij,df_c*b*f_a);
-	v3_add(&force,&force,&temp);
-	v3_scale(&force,&force,-0.5);
-
-	/* add force */
-	v3_add(&(ai->f),&(ai->f),&force);
+	/* reset zeta sum */
+	exchange->zeta_ij=0.0;
 
-	/* virial */
-	virial_calc(ai,&force,dist_ij);
-	//ai->virial.xx-=force.x*dist_ij->x;
-	//ai->virial.yy-=force.y*dist_ij->y;
-	//ai->virial.zz-=force.z*dist_ij->z;
-	//ai->virial.xy-=force.x*dist_ij->y;
-	//ai->virial.xz-=force.x*dist_ij->z;
-	//ai->virial.yz-=force.y*dist_ij->z;
+	/*
+	 * set ij depending values
+	 */
 
-#ifdef DEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVij (3bp) contrib:\n");
-	printf("%f | %f\n",force.x,ai->f.x);
-	printf("%f | %f\n",force.y,ai->f.y);
-	printf("%f | %f\n",force.z,ai->f.z);
-}
-#endif
-#ifdef VDEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVij (3bp) contrib:\n");
-	printf("%f | %f\n",force.x*dist_ij->x,ai->virial.xx);
-	printf("%f | %f\n",force.y*dist_ij->y,ai->virial.yy);
-	printf("%f | %f\n",force.z*dist_ij->z,ai->virial.zz);
-}
-#endif
+	brand=ai->brand;
+	
+	if(brand==aj->brand)
+		S2=params->S2[brand];
+	else
+		S2=params->S2mixed;
 
-	/* add energy of 3bp sum */
-	moldyn->energy+=(0.5*f_c*b*f_a);
+	/* dist_ij, d_ij2 */
+	v3_sub(&dist_ij,&(aj->r),&(ai->r));
+	if(bc) check_per_bound(moldyn,&dist_ij);
+	d_ij2=v3_absolute_square(&dist_ij);
 
-	/* dVji */
-	zeta=exchange->zeta_ji;
-	if(zeta==0.0) {
-		moldyn->debug++;
-		b=chi;
-		v3_scale(&force,dist_ij,df_a*b*f_c);
-	}
-	else {
-		tmp=betajnj*pow(zeta,nj-1.0);		/* beta^n * zeta^n-1 */
-		b=(1+zeta*tmp);				/* 1 + beta^n zeta^n */
-		db=chi*pow(b,-1.0/(2*nj)-1);		/* x(...)^(-1/2n - 1) */
-		b=db*b;					/* b_ij */
-		db*=-0.5*tmp;				/* db_ij */
-		v3_scale(&force,&(exchange->dzeta_ji),f_a*db);
-		v3_scale(&temp,dist_ij,df_a*b);
-		v3_add(&force,&force,&temp);
-		v3_scale(&force,&force,f_c);
+	/* if d_ij2 > S2 => no force & potential energy contribution */
+	if(d_ij2>S2) {
+		moldyn->run3bp=0;
+		return 0;
 	}
-	v3_scale(&temp,dist_ij,df_c*b*f_a);
-	v3_add(&force,&force,&temp);
-	v3_scale(&force,&force,-0.5);
 
-	/* add force */
-	v3_add(&(ai->f),&(ai->f),&force);
-
-	/* virial - plus sign, as dist_ij = - dist_ji - (really??) */
-// TEST ... with a minus instead
-	virial_calc(ai,&force,dist_ij);
-	//ai->virial.xx-=force.x*dist_ij->x;
-	//ai->virial.yy-=force.y*dist_ij->y;
-	//ai->virial.zz-=force.z*dist_ij->z;
-	//ai->virial.xy-=force.x*dist_ij->y;
-	//ai->virial.xz-=force.x*dist_ij->z;
-	//ai->virial.yz-=force.y*dist_ij->z;
+	/* d_ij */
+	d_ij=sqrt(d_ij2);
 
-#ifdef DEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVji (3bp) contrib:\n");
-	printf("%f | %f\n",force.x,ai->f.x);
-	printf("%f | %f\n",force.y,ai->f.y);
-	printf("%f | %f\n",force.z,ai->f.z);
-}
-#endif
-#ifdef VDEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVji (3bp) contrib:\n");
-	printf("%f | %f\n",force.x*dist_ij->x,ai->virial.xx);
-	printf("%f | %f\n",force.y*dist_ij->y,ai->virial.yy);
-	printf("%f | %f\n",force.z*dist_ij->z,ai->virial.zz);
-}
-#endif
+	/* store values */
+	exchange->dist_ij=dist_ij;
+	exchange->d_ij2=d_ij2;
+	exchange->d_ij=d_ij;
 
+	/* reset k counter for first k loop */
+	exchange->kcount=0;
+		
 	return 0;
 }
 
-/* tersoff 3 body part */
-
-int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
+/* tersoff 3 body potential function (first k loop) */
+int tersoff_mult_3bp_k1(t_moldyn *moldyn,
+                        t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
 
 	t_tersoff_mult_params *params;
 	t_tersoff_exchange *exchange;
-	t_3dvec dist_ij,dist_ik,dist_jk;
-	t_3dvec temp1,temp2;
-	t_3dvec *dzeta;
-	double R,S,S2,s_r;
-	double B,mu;
-	double d_ij,d_ik,d_jk,d_ij2,d_ik2,d_jk2;
-	double rr,dd;
-	double f_c,df_c;
-	double f_c_ik,df_c_ik,arg;
-	double f_c_jk;
-	double n,c,d,h;
-	double c2,d2,c2d2;
-	double cos_theta,d_costheta1,d_costheta2;
-	double h_cos,d2_h_cos2;
-	double frac,g,zeta,chi;
-	double tmp;
-	int brand;
+	unsigned char brand;
+	double R,S,S2;
+	t_3dvec dist_ij,dist_ik;
+	double d_ik2,d_ik,d_ij;
+	double cos_theta,h_cos,d2_h_cos2,frac,g,dg,s_r,arg;
+	double f_c_ik,df_c_ik;
+	int kcount;
 
 	params=moldyn->pot_params;
 	exchange=&(params->exchange);
+	kcount=exchange->kcount;
 
-	if(!(exchange->run3bp))
-		return 0;
-
-	/*
-	 * calc of 3bp contribution of V_ij and dV_ij/ji/jk &
-	 * 2bp contribution of dV_jk
-	 *
-	 * for Vij and dV_ij we still need:
-	 * - b_ij, db_ij (zeta_ij)
-	 *   - f_c_ik, df_c_ik, constants_i, cos_theta_ijk, d_costheta_ijk
-	 *
-	 * for dV_ji we still need:
-	 * - b_ji, db_ji (zeta_ji)
-	 *   - f_c_jk, d_c_jk, constants_j, cos_theta_jik, d_costheta_jik
-	 *
-	 * for dV_jk we need:
-	 * - f_c_jk
-	 * - f_a_jk
-	 * - db_jk (zeta_jk)
-	 *   - f_c_ji, df_c_ji, constants_j, cos_theta_jki, d_costheta_jki
-	 *
-	 */
-
-	/*
-	 * get exchange data 
-	 */
-
-	/* dist_ij, d_ij - this is < S_ij ! */
-	dist_ij=exchange->dist_ij;
-	d_ij=exchange->d_ij;
-	d_ij2=exchange->d_ij2;
-
-	/* f_c_ij, df_c_ij (same for ji) */
-	f_c=exchange->f_c;
-	df_c=exchange->df_c;
-
-	/*
-	 * calculate unknown values now ...
-	 */
-
-	/* V_ij and dV_ij stuff (in b_ij there is f_c_ik) */
-
-	/* dist_ik, d_ik */
-	v3_sub(&dist_ik,&(ak->r),&(ai->r));
-	if(bc) check_per_bound(moldyn,&dist_ik);
-	d_ik2=v3_absolute_square(&dist_ik);
+	if(kcount>TERSOFF_MAXN) {
+		printf("FATAL: neighbours = %d\n",kcount);
+		printf("  -> %d %d %d\n",ai->tag,aj->tag,ak->tag);
+	}
 
 	/* ik constants */
 	brand=ai->brand;
@@ -497,215 +270,298 @@ int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
 		S2=params->S2mixed;
 	}
 
-	/* zeta_ij/dzeta_ij contribution only for d_ik < S */
-	if(d_ik2<S2) {
-
-		/* now we need d_ik */
-		d_ik=sqrt(d_ik2);
-
-		/* get constants_i from exchange data */
-		n=*(exchange->n_i);
-		c=*(exchange->c_i);
-		d=*(exchange->d_i);
-		h=*(exchange->h_i);
-		c2=exchange->ci2;
-		d2=exchange->di2;
-		c2d2=exchange->ci2di2;
-
-		/* cosine of theta_ijk by scalaproduct */
-		rr=v3_scalar_product(&dist_ij,&dist_ik);
-		dd=d_ij*d_ik;
-		cos_theta=rr/dd;
-
-		/* d_costheta */
-		tmp=1.0/dd;
-		d_costheta1=cos_theta/d_ij2-tmp;
-		d_costheta2=cos_theta/d_ik2-tmp;
-
-		/* some usefull values */
-		h_cos=(h-cos_theta);
-		d2_h_cos2=d2+(h_cos*h_cos);
-		frac=c2/(d2_h_cos2);
-
-		/* g(cos_theta) */
-		g=1.0+c2d2-frac;
-
-		/* d_costheta_ij and dg(cos_theta) - needed in any case! */
-		v3_scale(&temp1,&dist_ij,d_costheta1);
-		v3_scale(&temp2,&dist_ik,d_costheta2);
-		v3_add(&temp1,&temp1,&temp2);
-		v3_scale(&temp1,&temp1,-2.0*frac*h_cos/d2_h_cos2); /* dg */
-
-		/* f_c_ik & df_c_ik + {d,}zeta contribution */
-		dzeta=&(exchange->dzeta_ij);
-		if(d_ik<R) {
-			/* {d,}f_c_ik */
-			// => f_c_ik=1.0;
-			// => df_c_ik=0.0; of course we do not set this!
-
-			/* zeta_ij */
-			exchange->zeta_ij+=g;
-
-			/* dzeta_ij */
-			v3_add(dzeta,dzeta,&temp1);
-		}
-		else {
-			/* {d,}f_c_ik */
-			s_r=S-R;
-			arg=M_PI*(d_ik-R)/s_r;
-			f_c_ik=0.5+0.5*cos(arg);
-			df_c_ik=0.5*sin(arg)*(M_PI/(s_r*d_ik));
-
-			/* zeta_ij */
-			exchange->zeta_ij+=f_c_ik*g;
-
-			/* dzeta_ij */
-			v3_scale(&temp1,&temp1,f_c_ik);
-			v3_scale(&temp2,&dist_ik,g*df_c_ik);
-			v3_add(&temp1,&temp1,&temp2);
-			v3_add(dzeta,dzeta,&temp1);
-		}
+	/* dist_ik, d_ik2 */
+	v3_sub(&dist_ik,&(ak->r),&(ai->r));
+	if(bc) check_per_bound(moldyn,&dist_ik);
+	d_ik2=v3_absolute_square(&dist_ik);
+
+	/* store data for second k loop */
+	exchange->dist_ik[kcount]=dist_ik;
+	exchange->d_ik2[kcount]=d_ik2;
+
+	/* return if not within cutoff */
+	if(d_ik2>S2) {
+		exchange->kcount++;
+		return 0;
+	}
+
+	/* d_ik */
+	d_ik=sqrt(d_ik2);
+
+	/* dist_ij, d_ij */
+	dist_ij=exchange->dist_ij;
+	d_ij=exchange->d_ij;
+
+	/* cos theta */
+	cos_theta=v3_scalar_product(&dist_ij,&dist_ik)/(d_ij*d_ik);
+
+	/* g_ijk */
+	h_cos=*(exchange->h_i)-cos_theta;
+	d2_h_cos2=exchange->di2+(h_cos*h_cos);
+	frac=exchange->ci2/d2_h_cos2;
+	g=1.0+exchange->ci2di2-frac;
+	dg=-2.0*frac*h_cos/d2_h_cos2;
+
+	/* zeta sum += f_c_ik * g_ijk */
+	if(d_ik<=R) {
+		exchange->zeta_ij+=g;
+		f_c_ik=1.0;
+		df_c_ik=0.0;
+	}
+	else {
+		s_r=S-R;
+		arg=M_PI*(d_ik-R)/s_r;
+		f_c_ik=0.5+0.5*cos(arg);
+		df_c_ik=0.5*sin(arg)*(M_PI/(s_r*d_ik));
+		exchange->zeta_ij+=f_c_ik*g;
 	}
 
-	/* dV_ji stuff (in b_ji there is f_c_jk) + dV_jk stuff! */
+	/* store even more data for second k loop */
+	exchange->g[kcount]=g;
+	exchange->dg[kcount]=dg;
+	exchange->d_ik[kcount]=d_ik;
+	exchange->cos_theta[kcount]=cos_theta;
+	exchange->f_c_ik[kcount]=f_c_ik;
+	exchange->df_c_ik[kcount]=df_c_ik;
 
-	/* dist_jk, d_jk */
-	v3_sub(&dist_jk,&(ak->r),&(aj->r));
-	if(bc) check_per_bound(moldyn,&dist_jk);
-	d_jk2=v3_absolute_square(&dist_jk);
+	/* increase k counter */
+	exchange->kcount++;
+
+	return 0;
+}
+
+int tersoff_mult_3bp_j2(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
+
+	t_tersoff_mult_params *params;
+	t_tersoff_exchange *exchange;
+	t_3dvec force;
+	double f_a,df_a,b,db,f_c,df_c;
+	double mu,B,chi;
+	double d_ij;
+	unsigned char brand;
+	double ni,tmp;
+	double S,R,s_r,arg;
+
+	params=moldyn->pot_params;
+	exchange=&(params->exchange);
 
-	/* jk constants */
 	brand=aj->brand;
-	if(brand==ak->brand) {
-		R=params->R[brand];
+	if(brand==ai->brand) {
 		S=params->S[brand];
-		S2=params->S2[brand];
+		R=params->R[brand];
 		B=params->B[brand];
 		mu=params->mu[brand];
 		chi=1.0;
 	}
 	else {
-		R=params->Rmixed;
 		S=params->Smixed;
-		S2=params->S2mixed;
+		R=params->Rmixed;
 		B=params->Bmixed;
 		mu=params->mu_m;
 		chi=params->chi;
 	}
 
-	/* zeta_ji/dzeta_ji contribution only for d_jk < S_jk */
-	if(d_jk2<S2) {
-
-		/* now we need d_ik */
-		d_jk=sqrt(d_jk2);
-
-		/* constants_j from exchange data */
-		n=*(exchange->n_j);
-		c=*(exchange->c_j);
-		d=*(exchange->d_j);
-		h=*(exchange->h_j);
-		c2=exchange->cj2;
-		d2=exchange->dj2;
-		c2d2=exchange->cj2dj2;
-
-		/* cosine of theta_jik by scalaproduct */
-		rr=-v3_scalar_product(&dist_ij,&dist_jk); /* -1, as ij -> ji */
-		dd=d_ij*d_jk;
-		cos_theta=rr/dd;
-
-		/* d_costheta */
-		d_costheta1=1.0/dd;
-		d_costheta2=cos_theta/d_ij2;
-
-		/* some usefull values */
-		h_cos=(h-cos_theta);
-		d2_h_cos2=d2+(h_cos*h_cos);
-		frac=c2/(d2_h_cos2);
-
-		/* g(cos_theta) */
-		g=1.0+c2d2-frac;
-
-		/* d_costheta_jik and dg(cos_theta) - needed in any case! */
-		v3_scale(&temp1,&dist_jk,d_costheta1);
-		v3_scale(&temp2,&dist_ij,-d_costheta2); /* ji -> ij => -1 */
-		//v3_add(&temp1,&temp1,&temp2);
-		v3_sub(&temp1,&temp1,&temp2); /* there is a minus! */
-		v3_scale(&temp1,&temp1,-2.0*frac*h_cos/d2_h_cos2); /* dg */
-
-		/* store dg in temp2 and use it for dVjk later */
-		v3_copy(&temp2,&temp1);
-
-		/* f_c_jk + {d,}zeta contribution (df_c_jk = 0) */
-		dzeta=&(exchange->dzeta_ji);
-		if(d_jk<R) {
-			/* f_c_jk */
-			f_c_jk=1.0;
-
-			/* zeta_ji */
-			exchange->zeta_ji+=g;
-
-			/* dzeta_ji */
-			v3_add(dzeta,dzeta,&temp1);
-		}
-		else {
-			/* f_c_jk */
-			s_r=S-R;
-			arg=M_PI*(d_jk-R)/s_r;
-			f_c_jk=0.5+0.5*cos(arg);
-
-			/* zeta_ji */
-			exchange->zeta_ji+=f_c_jk*g;
-
-			/* dzeta_ji */
-			v3_scale(&temp1,&temp1,f_c_jk);
-			v3_add(dzeta,dzeta,&temp1);
-		}
-
-		/* dV_jk stuff | add force contribution on atom i immediately */
-		if(exchange->d_ij_between_rs) {
-			zeta=f_c*g;
-			v3_scale(&temp1,&temp2,f_c);
-			v3_scale(&temp2,&dist_ij,df_c*g);
-			v3_add(&temp2,&temp2,&temp1); /* -> dzeta_jk in temp2 */
-		}
-		else {
-			zeta=g;
-			// dzeta_jk is simply dg, which is stored in temp2
-		}
-		/* betajnj * zeta_jk ^ nj-1 */
-		tmp=exchange->betajnj*pow(zeta,(n-1.0));
-		tmp=-chi/2.0*pow((1+tmp*zeta),(-1.0/(2.0*n)-1))*tmp;
-		v3_scale(&temp2,&temp2,tmp*B*exp(-mu*d_jk)*f_c_jk*0.5);
-		v3_add(&(ai->f),&(ai->f),&temp2); /* -1 skipped in f_a calc ^ */
-		                                  /* scaled with 0.5 ^ */
-
-		/* virial */
-		ai->virial.xx-=temp2.x*dist_jk.x;
-		ai->virial.yy-=temp2.y*dist_jk.y;
-		ai->virial.zz-=temp2.z*dist_jk.z;
-		ai->virial.xy-=temp2.x*dist_jk.y;
-		ai->virial.xz-=temp2.x*dist_jk.z;
-		ai->virial.yz-=temp2.y*dist_jk.z;
+	d_ij=exchange->d_ij;
+
+	/* f_c, df_c */
+	if(d_ij<R) {
+		f_c=1.0;
+		df_c=0.0;
+	}
+	else {
+		s_r=S-R;
+		arg=M_PI*(d_ij-R)/s_r;
+		f_c=0.5+0.5*cos(arg);
+		df_c=0.5*sin(arg)*(M_PI/(s_r*d_ij));
+	}
+
+	/* f_a, df_a */
+	f_a=-B*exp(-mu*d_ij);
+	df_a=mu*f_a/d_ij;
+
+	/* b, db */
+	if(exchange->zeta_ij==0.0) {
+		b=chi;
+		db=0.0;
+	}
+	else {
+		ni=*(exchange->n_i);
+		tmp=exchange->betaini*pow(exchange->zeta_ij,ni-1.0);
+		b=(1.0+exchange->zeta_ij*tmp);
+		db=chi*pow(b,-1.0/(2*ni)-1.0);
+		b=db*b;
+		db*=-0.5*tmp;
+	}
+
+	/* force contribution */
+	v3_scale(&force,&(exchange->dist_ij),df_a*f_c+f_a*df_c);
+	v3_scale(&force,&force,-0.5*b);
+	v3_add(&(ai->f),&(ai->f),&force);
+	v3_sub(&(aj->f),&(aj->f),&force);
 
 #ifdef DEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVjk (3bp) contrib:\n");
-	printf("%f | %f\n",temp2.x,ai->f.x);
-	printf("%f | %f\n",temp2.y,ai->f.y);
-	printf("%f | %f\n",temp2.z,ai->f.z);
-}
+	if((ai==&(moldyn->atom[0]))|(aj==&(moldyn->atom[0]))) {
+		printf("force 3bp (j2): [%d %d sum]\n",ai->tag,aj->tag);
+		printf("adding %f %f %f\n",force.x,force.y,force.z);
+		if(ai==&(moldyn->atom[0]))
+			printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
+		if(aj==&(moldyn->atom[0]))
+			printf("total j: %f %f %f\n",aj->f.x,aj->f.y,aj->f.z);
+	}
 #endif
-#ifdef VDEBUG
-if(ai==&(moldyn->atom[0])) {
-	printf("dVjk (3bp) contrib:\n");
-	printf("%f | %f\n",temp2.x*dist_jk.x,ai->virial.xx);
-	printf("%f | %f\n",temp2.y*dist_jk.y,ai->virial.yy);
-	printf("%f | %f\n",temp2.z*dist_jk.z,ai->virial.zz);
+
+	/* virial */
+	//virial_calc(ai,&force,&(exchange->dist_ij));
+	//virial_calc(aj,&force,&(exchange->dist_ij));
+
+	/* dzeta prefactor = - 0.5 f_c f_a db */
+	exchange->pre_dzeta=-0.5*f_a*f_c*db;
+
+	/* energy contribution */
+	moldyn->energy+=0.5*f_c*b*f_a;
+
+	/* reset k counter for second k loop */
+	exchange->kcount=0;
+		
+	return 0;
 }
+
+/* tersoff 3 body potential function (second k loop) */
+int tersoff_mult_3bp_k2(t_moldyn *moldyn,
+                        t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
+
+	t_tersoff_mult_params *params;
+	t_tersoff_exchange *exchange;
+	int kcount;
+	t_3dvec dist_ik,dist_ij;
+	double d_ik2,d_ik,d_ij2,d_ij;
+	unsigned char brand;
+	double S2;
+	double g,dg,cos_theta;
+	double pre_dzeta;
+	double f_c_ik,df_c_ik;
+	double dijdik_inv,fcdg,dfcg;
+	t_3dvec dcosdri,dcosdrj,dcosdrk;
+	t_3dvec force,tmp;
+
+	params=moldyn->pot_params;
+	exchange=&(params->exchange);
+	kcount=exchange->kcount;
+
+	if(kcount>TERSOFF_MAXN)
+		printf("FATAL: neighbours!\n");
+
+	/* d_ik2 */
+	d_ik2=exchange->d_ik2[kcount];
+
+	brand=ak->brand;
+	if(brand==ai->brand)
+		S2=params->S2[brand];
+	else
+		S2=params->S2mixed;
+
+	/* return if d_ik > S */
+	if(d_ik2>S2) {
+		exchange->kcount++;
+		return 0;
+	}
+
+	/* prefactor dzeta */
+	pre_dzeta=exchange->pre_dzeta;
+
+	/* dist_ik, d_ik */
+	dist_ik=exchange->dist_ik[kcount];
+	d_ik=exchange->d_ik[kcount];
+
+	/* f_c_ik, df_c_ik */
+	f_c_ik=exchange->f_c_ik[kcount];
+	df_c_ik=exchange->df_c_ik[kcount];
+
+	/* dist_ij, d_ij2, d_ij */
+	dist_ij=exchange->dist_ij;
+	d_ij2=exchange->d_ij2;
+	d_ij=exchange->d_ij;
+
+	/* g, dg, cos_theta */
+	g=exchange->g[kcount];
+	dg=exchange->dg[kcount];
+	cos_theta=exchange->cos_theta[kcount];
+
+	/* cos_theta derivatives wrt i,j,k */
+	dijdik_inv=1.0/(d_ij*d_ik);
+	v3_scale(&dcosdrj,&dist_ik,dijdik_inv);
+	v3_scale(&tmp,&dist_ij,-cos_theta/d_ij2);
+	v3_add(&dcosdrj,&dcosdrj,&tmp);
+	v3_scale(&dcosdrk,&dist_ij,dijdik_inv);
+	v3_scale(&tmp,&dist_ik,-cos_theta/d_ik2);
+	v3_add(&dcosdrk,&dcosdrk,&tmp);
+	v3_add(&dcosdri,&dcosdrj,&dcosdrk);
+	v3_scale(&dcosdri,&dcosdri,-1.0);
+
+	/* f_c_ik * dg, df_c_ik * g */
+	fcdg=f_c_ik*dg;
+	dfcg=df_c_ik*g;
+
+	/* derivative wrt i */
+	v3_scale(&force,&dist_ik,dfcg);
+	v3_scale(&tmp,&dcosdri,fcdg);
+	v3_add(&force,&force,&tmp);
+	v3_scale(&force,&force,pre_dzeta);
+
+	/* force contribution */
+	v3_add(&(ai->f),&(ai->f),&force);
+	
+#ifdef DEBUG
+	if(ai==&(moldyn->atom[0])) {
+		printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
+		printf("adding %f %f %f\n",force.x,force.y,force.z);
+		printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
+	}
+#endif
+
+	/* virial */
+	//virial_calc(ai,&force,&dist_ij);
+
+	/* derivatice wrt j */
+	v3_scale(&force,&dcosdrj,fcdg*pre_dzeta);
+
+	/* force contribution */
+	v3_add(&(aj->f),&(aj->f),&force);
+
+#ifdef DEBUG
+	if(aj==&(moldyn->atom[0])) {
+		printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
+		printf("adding %f %f %f\n",force.x,force.y,force.z);
+		printf("total j: %f %f %f\n",aj->f.x,aj->f.y,aj->f.z);
+	}
 #endif
 
+	/* virial */
+	//virial_calc(aj,&force,&dist_ij);
+
+	/* derivative wrt k */
+	v3_scale(&force,&dist_ik,dfcg);
+	v3_scale(&tmp,&dcosdrk,fcdg);
+	v3_add(&force,&force,&tmp);
+	v3_scale(&force,&force,pre_dzeta);
+
+	/* force contribution */
+	v3_add(&(ak->f),&(ak->f),&force);
+
+#ifdef DEBUG
+	if(ak==&(moldyn->atom[0])) {
+		printf("force 3bp (k2): [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
+		printf("adding %f %f %f\n",force.x,force.y,force.z);
+		printf("total k: %f %f %f\n",ak->f.x,ak->f.y,ak->f.z);
 	}
+#endif
+
+	/* virial */
+	virial_calc(ak,&force,&dist_ik);
+	
+	/* increase k counter */
+	exchange->kcount++;	
 
 	return 0;
-}
 
+}
diff --git a/potentials/tersoff.h b/potentials/tersoff.h
index a04ed02..52e848f 100644
--- a/potentials/tersoff.h
+++ b/potentials/tersoff.h
@@ -8,45 +8,41 @@
 #ifndef TERSOFF_H
 #define TERSOFF_H
 
+#define TERSOFF_MAXN	16*27
+
 /* tersoff exchange type */
 typedef struct s_tersoff_echange {
-	double f_c,df_c;
-	double f_a,df_a;
 
 	t_3dvec dist_ij;
 	double d_ij2;
 	double d_ij;
 
-	double chi;
+	t_3dvec dist_ik[TERSOFF_MAXN];
+	double d_ik2[TERSOFF_MAXN];
+	double d_ik[TERSOFF_MAXN];
+
+	double f_c_ik[TERSOFF_MAXN];
+	double df_c_ik[TERSOFF_MAXN];
+
+	double g[TERSOFF_MAXN];
+	double dg[TERSOFF_MAXN];
+	double cos_theta[TERSOFF_MAXN];
 
 	double *beta_i;
-	double *beta_j;
 	double *n_i;
-	double *n_j;
 	double *c_i;
-	double *c_j;
 	double *d_i;
-	double *d_j;
 	double *h_i;
-	double *h_j;
 
 	double ci2;
-	double cj2;
 	double di2;
-	double dj2;
 	double ci2di2;
-	double cj2dj2;
 	double betaini;
-	double betajnj;
-
-	u8 run3bp;
-	u8 run2bp_post;
-	u8 d_ij_between_rs;
 
 	double zeta_ij;
-	double zeta_ji;
-	t_3dvec dzeta_ij;
-	t_3dvec dzeta_ji;
+	double pre_dzeta;
+
+	int kcount;
 } t_tersoff_exchange;
 
 /* tersoff mult (2!) potential parameters */
@@ -81,7 +77,11 @@ typedef struct s_tersoff_mult_params {
 int tersoff_mult_complete_params(t_tersoff_mult_params *p);
 int tersoff_mult_1bp(t_moldyn *moldyn,t_atom *ai);
 int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
-int tersoff_mult_post_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
-int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc);
+int tersoff_mult_3bp_j1(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
+int tersoff_mult_3bp_k1(t_moldyn *moldyn,
+                        t_atom *ai,t_atom *aj,t_atom *ak,u8 bc);
+int tersoff_mult_3bp_j2(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
+int tersoff_mult_3bp_k2(t_moldyn *moldyn,
+                        t_atom *ai,t_atom *aj,t_atom *ak,u8 bc);
 
 #endif
diff --git a/potentials/tersoff_orig.c b/potentials/tersoff_orig.c
new file mode 100644
index 0000000..90121f2
--- /dev/null
+++ b/potentials/tersoff_orig.c
@@ -0,0 +1,707 @@
+/*
+ * tersoff_orig.c - tersoff potential
+ *
+ * author: Frank Zirkelbach <frank.zirkelbach@physik.uni-augsburg.de>
+ *
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <math.h>
+
+#include "../moldyn.h"
+#include "../math/math.h"
+#include "tersoff_orig.h"
+
+/* create mixed terms from parameters and set them */
+int tersoff_mult_complete_params(t_tersoff_mult_params *p) {
+
+	printf("[moldyn] tersoff parameter completion\n");
+	p->S2[0]=p->S[0]*p->S[0];
+	p->S2[1]=p->S[1]*p->S[1];
+	p->Smixed=sqrt(p->S[0]*p->S[1]);
+	p->S2mixed=p->Smixed*p->Smixed;
+	p->Rmixed=sqrt(p->R[0]*p->R[1]);
+	p->Amixed=sqrt(p->A[0]*p->A[1]);
+	p->Bmixed=sqrt(p->B[0]*p->B[1]);
+	p->lambda_m=0.5*(p->lambda[0]+p->lambda[1]);
+	p->mu_m=0.5*(p->mu[0]+p->mu[1]);
+
+	printf("[moldyn] tersoff mult parameter info:\n");
+	printf("  S (A)  | %f | %f | %f\n",p->S[0],p->S[1],p->Smixed);
+	printf("  R (A)  | %f | %f | %f\n",p->R[0],p->R[1],p->Rmixed);
+	printf("  A (eV) | %f | %f | %f\n",p->A[0]/EV,p->A[1]/EV,p->Amixed/EV);
+	printf("  B (eV) | %f | %f | %f\n",p->B[0]/EV,p->B[1]/EV,p->Bmixed/EV);
+	printf("  lambda | %f | %f | %f\n",p->lambda[0],p->lambda[1],
+	                                  p->lambda_m);
+	printf("  mu     | %f | %f | %f\n",p->mu[0],p->mu[1],p->mu_m);
+	printf("  beta   | %.10f | %.10f\n",p->beta[0],p->beta[1]);
+	printf("  n      | %f | %f\n",p->n[0],p->n[1]);
+	printf("  c      | %f | %f\n",p->c[0],p->c[1]);
+	printf("  d      | %f | %f\n",p->d[0],p->d[1]);
+	printf("  h      | %f | %f\n",p->h[0],p->h[1]);
+	printf("  chi    | %f \n",p->chi);
+
+	return 0;
+}
+
+/* tersoff 1 body part */
+int tersoff_mult_1bp(t_moldyn *moldyn,t_atom *ai) {
+
+	int brand;
+	t_tersoff_mult_params *params;
+	t_tersoff_exchange *exchange;
+	
+	brand=ai->brand;
+	params=moldyn->pot_params;
+	exchange=&(params->exchange);
+
+	/*
+	 * simple: point constant parameters only depending on atom i to
+	 *         their right values
+	 */
+
+	exchange->beta_i=&(params->beta[brand]);
+	exchange->n_i=&(params->n[brand]);
+	exchange->c_i=&(params->c[brand]);
+	exchange->d_i=&(params->d[brand]);
+	exchange->h_i=&(params->h[brand]);
+
+	exchange->betaini=pow(*(exchange->beta_i),*(exchange->n_i));
+	exchange->ci2=params->c[brand]*params->c[brand];
+	exchange->di2=params->d[brand]*params->d[brand];
+	exchange->ci2di2=exchange->ci2/exchange->di2;
+
+	return 0;
+}
+	
+/* tersoff 2 body part */
+int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
+
+	t_tersoff_mult_params *params;
+	t_tersoff_exchange *exchange;
+	t_3dvec dist_ij,force;
+	double d_ij,d_ij2;
+	double A,B,R,S,S2,lambda,mu;
+	double f_r,df_r;
+	double f_c,df_c;
+	int brand;
+	double s_r;
+	double arg;
+
+	/* use newtons third law */
+	//if(ai<aj) return 0;
+
+	params=moldyn->pot_params;
+	brand=aj->brand;
+	exchange=&(params->exchange);
+
+	/* clear 3bp and 2bp post run */
+	exchange->run3bp=0;
+	exchange->run2bp_post=0;
+
+	/* reset S > r > R mark */
+	exchange->d_ij_between_rs=0;
+	
+	/*
+	 * calc of 2bp contribution of V_ij and dV_ij/ji
+	 *
+	 * for Vij and dV_ij we need:
+	 * - f_c_ij, df_c_ij
+	 * - f_r_ij, df_r_ij
+	 *
+	 * for dV_ji we need:
+	 * - f_c_ji = f_c_ij, df_c_ji = df_c_ij
+	 * - f_r_ji = f_r_ij; df_r_ji = df_r_ij
+	 *
+	 */
+
+	/* determine cutoff square */
+	if(brand==ai->brand)
+		S2=params->S2[brand];
+	else
+		S2=params->S2mixed;
+
+	/* dist_ij, d_ij */
+	v3_sub(&dist_ij,&(aj->r),&(ai->r));
+	if(bc) check_per_bound(moldyn,&dist_ij);
+	d_ij2=v3_absolute_square(&dist_ij);
+
+	/* if d_ij2 > S2 => no force & potential energy contribution */
+	if(d_ij2>S2)
+		return 0;
+
+	/* now we will need the distance */
+	//d_ij=v3_norm(&dist_ij);
+	d_ij=sqrt(d_ij2);
+
+	/* save for use in 3bp */
+	exchange->d_ij=d_ij;
+	exchange->d_ij2=d_ij2;
+	exchange->dist_ij=dist_ij;
+
+	/* more constants */
+	exchange->beta_j=&(params->beta[brand]);
+	exchange->n_j=&(params->n[brand]);
+	exchange->c_j=&(params->c[brand]);
+	exchange->d_j=&(params->d[brand]);
+	exchange->h_j=&(params->h[brand]);
+	if(brand==ai->brand) {
+		S=params->S[brand];
+		R=params->R[brand];
+		A=params->A[brand];
+		B=params->B[brand];
+		lambda=params->lambda[brand];
+		mu=params->mu[brand];
+		exchange->chi=1.0;
+		exchange->betajnj=exchange->betaini;
+		exchange->cj2=exchange->ci2;
+		exchange->dj2=exchange->di2;
+		exchange->cj2dj2=exchange->ci2di2;
+	}
+	else {
+		S=params->Smixed;
+		R=params->Rmixed;
+		A=params->Amixed;
+		B=params->Bmixed;
+		lambda=params->lambda_m;
+		mu=params->mu_m;
+		exchange->chi=params->chi;
+		exchange->betajnj=pow(*(exchange->beta_j),*(exchange->n_j));
+		exchange->cj2=params->c[brand]*params->c[brand];
+		exchange->dj2=params->d[brand]*params->d[brand];
+		exchange->cj2dj2=exchange->cj2/exchange->dj2;
+	}
+
+	/* f_r_ij = f_r_ji, df_r_ij = df_r_ji */
+	f_r=A*exp(-lambda*d_ij);
+	df_r=lambda*f_r/d_ij;
+
+	/* f_a, df_a calc (again, same for ij and ji) | save for later use! */
+	exchange->f_a=-B*exp(-mu*d_ij);
+	exchange->df_a=mu*exchange->f_a/d_ij;
+
+	/* f_c, df_c calc (again, same for ij and ji) */
+	if(d_ij<R) {
+		/* f_c = 1, df_c = 0 */
+		f_c=1.0;
+		df_c=0.0;
+		/* two body contribution (ij, ji) */
+		v3_scale(&force,&dist_ij,-df_r);
+	}
+	else {
+		s_r=S-R;
+		arg=M_PI*(d_ij-R)/s_r;
+		f_c=0.5+0.5*cos(arg);
+		df_c=0.5*sin(arg)*(M_PI/(s_r*d_ij));
+		/* two body contribution (ij, ji) */
+		v3_scale(&force,&dist_ij,-df_c*f_r-df_r*f_c);
+		/* tell 3bp that S > r > R */
+		exchange->d_ij_between_rs=1;
+	}
+
+	/* add forces of 2bp (ij, ji) contribution
+	 * dVij = dVji and we sum up both: no 1/2) */
+	v3_add(&(ai->f),&(ai->f),&force);
+
+	/* virial */
+	virial_calc(ai,&force,&dist_ij);
+	//ai->virial.xx-=force.x*dist_ij.x;
+	//ai->virial.yy-=force.y*dist_ij.y;
+	//ai->virial.zz-=force.z*dist_ij.z;
+	//ai->virial.xy-=force.x*dist_ij.y;
+	//ai->virial.xz-=force.x*dist_ij.z;
+	//ai->virial.yz-=force.y*dist_ij.z;
+
+#ifdef DEBUG
+if(ai==&(moldyn->atom[0])) {
+	printf("dVij, dVji (2bp) contrib: [%d %d]\n",ai->tag,aj->tag);
+	printf("adding %f %f %f\n",force.x,force.y,force.z);
+	printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
+}
+#endif
+#ifdef VDEBUG
+if(ai==&(moldyn->atom[0])) {
+	printf("dVij, dVji (2bp) contrib:\n");
+	printf("%f | %f\n",force.x*dist_ij.x,ai->virial.xx);
+	printf("%f | %f\n",force.y*dist_ij.y,ai->virial.yy);
+	printf("%f | %f\n",force.z*dist_ij.z,ai->virial.zz);
+}
+#endif
+
+	/* energy 2bp contribution (ij, ji) is 0.5 f_r f_c ... */
+	moldyn->energy+=(0.5*f_r*f_c);
+
+	/* save for use in 3bp */
+	exchange->f_c=f_c;
+	exchange->df_c=df_c;
+
+	/* enable the run of 3bp function and 2bp post processing */
+	exchange->run3bp=1;
+	exchange->run2bp_post=1;
+
+	/* reset 3bp sums */
+	exchange->zeta_ij=0.0;
+	exchange->zeta_ji=0.0;
+	v3_zero(&(exchange->dzeta_ij));
+	v3_zero(&(exchange->dzeta_ji));
+
+	return 0;
+}
+
+/* tersoff 2 body post part */
+
+int tersoff_mult_post_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc) {
+
+	/*
+	 * here we have to allow for the 3bp sums
+	 *
+	 * that is:
+	 * - zeta_ij, dzeta_ij
+	 * - zeta_ji, dzeta_ji
+	 *
+	 * to compute the 3bp contribution to:
+	 * - Vij, dVij
+	 * - dVji
+	 *
+	 */
+
+	t_tersoff_mult_params *params;
+	t_tersoff_exchange *exchange;
+
+	t_3dvec force,temp;
+	t_3dvec *dist_ij;
+	double b,db,tmp;
+	double f_c,df_c,f_a,df_a;
+	double chi,ni,betaini,nj,betajnj;
+	double zeta;
+
+	params=moldyn->pot_params;
+	exchange=&(params->exchange);
+
+	/* we do not run if f_c_ij was detected to be 0! */
+	if(!(exchange->run2bp_post))
+		return 0;
+
+	f_c=exchange->f_c;
+	df_c=exchange->df_c;
+	f_a=exchange->f_a;
+	df_a=exchange->df_a;
+	betaini=exchange->betaini;
+	betajnj=exchange->betajnj;
+	ni=*(exchange->n_i);
+	nj=*(exchange->n_j);
+	chi=exchange->chi;
+	dist_ij=&(exchange->dist_ij);
+	
+	/* Vij and dVij */
+	zeta=exchange->zeta_ij;
+	if(zeta==0.0) {
+		moldyn->debug++;		/* just for debugging ... */
+		b=chi;
+		v3_scale(&force,dist_ij,df_a*b*f_c);
+	}
+	else {
+		tmp=betaini*pow(zeta,ni-1.0);		/* beta^n * zeta^n-1 */
+		b=(1+zeta*tmp);				/* 1 + beta^n zeta^n */
+		db=chi*pow(b,-1.0/(2*ni)-1);		/* x(...)^(-1/2n - 1) */
+		b=db*b;					/* b_ij */
+		db*=-0.5*tmp;				/* db_ij */
+		v3_scale(&force,&(exchange->dzeta_ij),f_a*db);
+		v3_scale(&temp,dist_ij,df_a*b);
+		v3_add(&force,&force,&temp);
+		v3_scale(&force,&force,f_c);
+	}
+	v3_scale(&temp,dist_ij,df_c*b*f_a);
+	v3_add(&force,&force,&temp);
+	v3_scale(&force,&force,-0.5);
+
+	/* add force */
+	v3_add(&(ai->f),&(ai->f),&force);
+
+	/* virial */
+	virial_calc(ai,&force,dist_ij);
+	//ai->virial.xx-=force.x*dist_ij->x;
+	//ai->virial.yy-=force.y*dist_ij->y;
+	//ai->virial.zz-=force.z*dist_ij->z;
+	//ai->virial.xy-=force.x*dist_ij->y;
+	//ai->virial.xz-=force.x*dist_ij->z;
+	//ai->virial.yz-=force.y*dist_ij->z;
+
+#ifdef DEBUG
+if(ai==&(moldyn->atom[0])) {
+	printf("dVij (3bp) contrib: [%d %d sum]\n",ai->tag,aj->tag);
+	printf("adding %f %f %f\n",force.x,force.y,force.z);
+	printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
+}
+#endif
+#ifdef VDEBUG
+if(ai==&(moldyn->atom[0])) {
+	printf("dVij (3bp) contrib:\n");
+	printf("%f | %f\n",force.x*dist_ij->x,ai->virial.xx);
+	printf("%f | %f\n",force.y*dist_ij->y,ai->virial.yy);
+	printf("%f | %f\n",force.z*dist_ij->z,ai->virial.zz);
+}
+#endif
+
+	/* add energy of 3bp sum */
+	moldyn->energy+=(0.5*f_c*b*f_a);
+
+	/* dVji */
+	zeta=exchange->zeta_ji;
+	if(zeta==0.0) {
+		moldyn->debug++;
+		b=chi;
+		v3_scale(&force,dist_ij,df_a*b*f_c);
+	}
+	else {
+		tmp=betajnj*pow(zeta,nj-1.0);		/* beta^n * zeta^n-1 */
+		b=(1+zeta*tmp);				/* 1 + beta^n zeta^n */
+		db=chi*pow(b,-1.0/(2*nj)-1);		/* x(...)^(-1/2n - 1) */
+		b=db*b;					/* b_ij */
+		db*=-0.5*tmp;				/* db_ij */
+		v3_scale(&force,&(exchange->dzeta_ji),f_a*db);
+		v3_scale(&temp,dist_ij,df_a*b);
+		v3_add(&force,&force,&temp);
+		v3_scale(&force,&force,f_c);
+	}
+	v3_scale(&temp,dist_ij,df_c*b*f_a);
+	v3_add(&force,&force,&temp);
+	v3_scale(&force,&force,-0.5);
+
+	/* add force */
+	v3_add(&(ai->f),&(ai->f),&force);
+
+	/* virial - plus sign, as dist_ij = - dist_ji - (really??) */
+// TEST ... with a minus instead
+	virial_calc(ai,&force,dist_ij);
+	//ai->virial.xx-=force.x*dist_ij->x;
+	//ai->virial.yy-=force.y*dist_ij->y;
+	//ai->virial.zz-=force.z*dist_ij->z;
+	//ai->virial.xy-=force.x*dist_ij->y;
+	//ai->virial.xz-=force.x*dist_ij->z;
+	//ai->virial.yz-=force.y*dist_ij->z;
+
+#ifdef DEBUG
+if(ai==&(moldyn->atom[0])) {
+	printf("dVji (3bp) contrib: [%d %d sum]\n",ai->tag,aj->tag);
+	printf("adding %f %f %f\n",force.x,force.y,force.z);
+	printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
+}
+#endif
+#ifdef VDEBUG
+if(ai==&(moldyn->atom[0])) {
+	printf("dVji (3bp) contrib:\n");
+	printf("%f | %f\n",force.x*dist_ij->x,ai->virial.xx);
+	printf("%f | %f\n",force.y*dist_ij->y,ai->virial.yy);
+	printf("%f | %f\n",force.z*dist_ij->z,ai->virial.zz);
+}
+#endif
+
+	return 0;
+}
+
+/* tersoff 3 body part */
+
+int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc) {
+
+	t_tersoff_mult_params *params;
+	t_tersoff_exchange *exchange;
+	t_3dvec dist_ij,dist_ik,dist_jk;
+	t_3dvec temp1,temp2;
+	t_3dvec *dzeta;
+	double R,S,S2,s_r;
+	double B,mu;
+	double d_ij,d_ik,d_jk,d_ij2,d_ik2,d_jk2;
+	double rr,dd;
+	double f_c,df_c;
+	double f_c_ik,df_c_ik,arg;
+	double f_c_jk;
+	double n,c,d,h;
+	double c2,d2,c2d2;
+	double cos_theta,d_costheta1,d_costheta2;
+	double h_cos,d2_h_cos2;
+	double frac,g,zeta,chi;
+	double tmp;
+	int brand;
+
+	params=moldyn->pot_params;
+	exchange=&(params->exchange);
+
+	if(!(exchange->run3bp))
+		return 0;
+
+	/*
+	 * calc of 3bp contribution of V_ij and dV_ij/ji/jk &
+	 * 2bp contribution of dV_jk
+	 *
+	 * for Vij and dV_ij we still need:
+	 * - b_ij, db_ij (zeta_ij)
+	 *   - f_c_ik, df_c_ik, constants_i, cos_theta_ijk, d_costheta_ijk
+	 *
+	 * for dV_ji we still need:
+	 * - b_ji, db_ji (zeta_ji)
+	 *   - f_c_jk, d_c_jk, constants_j, cos_theta_jik, d_costheta_jik
+	 *
+	 * for dV_jk we need:
+	 * - f_c_jk
+	 * - f_a_jk
+	 * - db_jk (zeta_jk)
+	 *   - f_c_ji, df_c_ji, constants_j, cos_theta_jki, d_costheta_jki
+	 *
+	 */
+
+	/*
+	 * get exchange data 
+	 */
+
+	/* dist_ij, d_ij - this is < S_ij ! */
+	dist_ij=exchange->dist_ij;
+	d_ij=exchange->d_ij;
+	d_ij2=exchange->d_ij2;
+
+	/* f_c_ij, df_c_ij (same for ji) */
+	f_c=exchange->f_c;
+	df_c=exchange->df_c;
+
+	/*
+	 * calculate unknown values now ...
+	 */
+
+	/* V_ij and dV_ij stuff (in b_ij there is f_c_ik) */
+
+	/* dist_ik, d_ik */
+	v3_sub(&dist_ik,&(ak->r),&(ai->r));
+	if(bc) check_per_bound(moldyn,&dist_ik);
+	d_ik2=v3_absolute_square(&dist_ik);
+
+	/* ik constants */
+	brand=ai->brand;
+	if(brand==ak->brand) {
+		R=params->R[brand];
+		S=params->S[brand];
+		S2=params->S2[brand];
+	}
+	else {
+		R=params->Rmixed;
+		S=params->Smixed;
+		S2=params->S2mixed;
+	}
+
+	/* zeta_ij/dzeta_ij contribution only for d_ik < S */
+	if(d_ik2<S2) {
+
+		/* now we need d_ik */
+		d_ik=sqrt(d_ik2);
+
+		/* get constants_i from exchange data */
+		n=*(exchange->n_i);
+		c=*(exchange->c_i);
+		d=*(exchange->d_i);
+		h=*(exchange->h_i);
+		c2=exchange->ci2;
+		d2=exchange->di2;
+		c2d2=exchange->ci2di2;
+
+		/* cosine of theta_ijk by scalaproduct */
+		rr=v3_scalar_product(&dist_ij,&dist_ik);
+		dd=d_ij*d_ik;
+		cos_theta=rr/dd;
+
+		/* d_costheta */
+		tmp=1.0/dd;
+		d_costheta1=cos_theta/d_ij2-tmp;
+		d_costheta2=cos_theta/d_ik2-tmp;
+
+		/* some usefull values */
+		h_cos=(h-cos_theta);
+		d2_h_cos2=d2+(h_cos*h_cos);
+		frac=c2/(d2_h_cos2);
+
+		/* g(cos_theta) */
+		g=1.0+c2d2-frac;
+
+		/* d_costheta_ij and dg(cos_theta) - needed in any case! */
+		v3_scale(&temp1,&dist_ij,d_costheta1);
+		v3_scale(&temp2,&dist_ik,d_costheta2);
+		v3_add(&temp1,&temp1,&temp2);
+		v3_scale(&temp1,&temp1,-2.0*frac*h_cos/d2_h_cos2); /* dg */
+
+		/* f_c_ik & df_c_ik + {d,}zeta contribution */
+		dzeta=&(exchange->dzeta_ij);
+		if(d_ik<R) {
+			/* {d,}f_c_ik */
+			// => f_c_ik=1.0;
+			// => df_c_ik=0.0; of course we do not set this!
+
+			/* zeta_ij */
+			exchange->zeta_ij+=g;
+
+			/* dzeta_ij */
+			v3_add(dzeta,dzeta,&temp1);
+		}
+		else {
+			/* {d,}f_c_ik */
+			s_r=S-R;
+			arg=M_PI*(d_ik-R)/s_r;
+			f_c_ik=0.5+0.5*cos(arg);
+			df_c_ik=0.5*sin(arg)*(M_PI/(s_r*d_ik));
+
+			/* zeta_ij */
+			exchange->zeta_ij+=f_c_ik*g;
+
+			/* dzeta_ij */
+			v3_scale(&temp1,&temp1,f_c_ik);
+			v3_scale(&temp2,&dist_ik,g*df_c_ik);
+			v3_add(&temp1,&temp1,&temp2);
+			v3_add(dzeta,dzeta,&temp1);
+		}
+	}
+
+	/* dV_ji stuff (in b_ji there is f_c_jk) + dV_jk stuff! */
+
+	/* dist_jk, d_jk */
+	v3_sub(&dist_jk,&(ak->r),&(aj->r));
+	if(bc) check_per_bound(moldyn,&dist_jk);
+	d_jk2=v3_absolute_square(&dist_jk);
+
+	/* jk constants */
+	brand=aj->brand;
+	if(brand==ak->brand) {
+		R=params->R[brand];
+		S=params->S[brand];
+		S2=params->S2[brand];
+		B=params->B[brand];
+		mu=params->mu[brand];
+		chi=1.0;
+	}
+	else {
+		R=params->Rmixed;
+		S=params->Smixed;
+		S2=params->S2mixed;
+		B=params->Bmixed;
+		mu=params->mu_m;
+		chi=params->chi;
+	}
+
+	/* zeta_ji/dzeta_ji contribution only for d_jk < S_jk */
+	if(d_jk2<S2) {
+
+		/* now we need d_ik */
+		d_jk=sqrt(d_jk2);
+
+		/* constants_j from exchange data */
+		n=*(exchange->n_j);
+		c=*(exchange->c_j);
+		d=*(exchange->d_j);
+		h=*(exchange->h_j);
+		c2=exchange->cj2;
+		d2=exchange->dj2;
+		c2d2=exchange->cj2dj2;
+
+		/* cosine of theta_jik by scalaproduct */
+		rr=-v3_scalar_product(&dist_ij,&dist_jk); /* -1, as ij -> ji */
+		dd=d_ij*d_jk;
+		cos_theta=rr/dd;
+
+		/* d_costheta */
+		d_costheta1=1.0/dd;
+		d_costheta2=cos_theta/d_ij2;
+
+		/* some usefull values */
+		h_cos=(h-cos_theta);
+		d2_h_cos2=d2+(h_cos*h_cos);
+		frac=c2/(d2_h_cos2);
+
+		/* g(cos_theta) */
+		g=1.0+c2d2-frac;
+
+		/* d_costheta_jik and dg(cos_theta) - needed in any case! */
+		v3_scale(&temp1,&dist_jk,d_costheta1);
+		v3_scale(&temp2,&dist_ij,-d_costheta2); /* ji -> ij => -1 */
+		//v3_add(&temp1,&temp1,&temp2);
+		v3_sub(&temp1,&temp1,&temp2); /* there is a minus! */
+		v3_scale(&temp1,&temp1,-2.0*frac*h_cos/d2_h_cos2); /* dg */
+
+		/* store dg in temp2 and use it for dVjk later */
+		v3_copy(&temp2,&temp1);
+
+		/* f_c_jk + {d,}zeta contribution (df_c_jk = 0) */
+		dzeta=&(exchange->dzeta_ji);
+		if(d_jk<R) {
+			/* f_c_jk */
+			f_c_jk=1.0;
+
+			/* zeta_ji */
+			exchange->zeta_ji+=g;
+
+			/* dzeta_ji */
+			v3_add(dzeta,dzeta,&temp1);
+		}
+		else {
+			/* f_c_jk */
+			s_r=S-R;
+			arg=M_PI*(d_jk-R)/s_r;
+			f_c_jk=0.5+0.5*cos(arg);
+
+			/* zeta_ji */
+			exchange->zeta_ji+=f_c_jk*g;
+
+			/* dzeta_ji */
+			v3_scale(&temp1,&temp1,f_c_jk);
+			v3_add(dzeta,dzeta,&temp1);
+		}
+
+		/* dV_jk stuff | add force contribution on atom i immediately */
+		if(exchange->d_ij_between_rs) {
+			zeta=f_c*g;
+			v3_scale(&temp1,&temp2,f_c);
+			v3_scale(&temp2,&dist_ij,df_c*g);
+			v3_add(&temp2,&temp2,&temp1); /* -> dzeta_jk in temp2 */
+		}
+		else {
+			zeta=g;
+			// dzeta_jk is simply dg, which is stored in temp2
+		}
+		/* betajnj * zeta_jk ^ nj-1 */
+		tmp=exchange->betajnj*pow(zeta,(n-1.0));
+		tmp=-chi/2.0*pow((1+tmp*zeta),(-1.0/(2.0*n)-1))*tmp;
+		v3_scale(&temp2,&temp2,tmp*B*exp(-mu*d_jk)*f_c_jk*0.5);
+		v3_add(&(ai->f),&(ai->f),&temp2); /* -1 skipped in f_a calc ^ */
+		                                  /* scaled with 0.5 ^ */
+
+		/* virial */
+		ai->virial.xx-=temp2.x*dist_jk.x;
+		ai->virial.yy-=temp2.y*dist_jk.y;
+		ai->virial.zz-=temp2.z*dist_jk.z;
+		ai->virial.xy-=temp2.x*dist_jk.y;
+		ai->virial.xz-=temp2.x*dist_jk.z;
+		ai->virial.yz-=temp2.y*dist_jk.z;
+
+#ifdef DEBUG
+if(ai==&(moldyn->atom[0])) {
+	printf("dVjk (3bp) contrib: [%d %d %d]\n",ai->tag,aj->tag,ak->tag);
+	printf("adding %f %f %f\n",temp2.x,temp2.y,temp2.z);
+	printf("total i: %f %f %f\n",ai->f.x,ai->f.y,ai->f.z);
+}
+#endif
+#ifdef VDEBUG
+if(ai==&(moldyn->atom[0])) {
+	printf("dVjk (3bp) contrib:\n");
+	printf("%f | %f\n",temp2.x*dist_jk.x,ai->virial.xx);
+	printf("%f | %f\n",temp2.y*dist_jk.y,ai->virial.yy);
+	printf("%f | %f\n",temp2.z*dist_jk.z,ai->virial.zz);
+}
+#endif
+
+	}
+
+	return 0;
+}
+
diff --git a/potentials/tersoff_orig.h b/potentials/tersoff_orig.h
new file mode 100644
index 0000000..d5d4a66
--- /dev/null
+++ b/potentials/tersoff_orig.h
@@ -0,0 +1,87 @@
+/*
+ * tersoff_orig.h - tersoff potential header file
+ *
+ * author: Frank Zirkelbach <frank.zirkelbach@physik.uni-augsburg.de>
+ *
+ */
+
+#ifndef TERSOFF_H
+#define TERSOFF_H
+
+/* tersoff exchange type */
+typedef struct s_tersoff_echange {
+	double f_c,df_c;
+	double f_a,df_a;
+
+	t_3dvec dist_ij;
+	double d_ij2;
+	double d_ij;
+
+	double chi;
+
+	double *beta_i;
+	double *beta_j;
+	double *n_i;
+	double *n_j;
+	double *c_i;
+	double *c_j;
+	double *d_i;
+	double *d_j;
+	double *h_i;
+	double *h_j;
+
+	double ci2;
+	double cj2;
+	double di2;
+	double dj2;
+	double ci2di2;
+	double cj2dj2;
+	double betaini;
+	double betajnj;
+
+	u8 run3bp;
+	u8 run2bp_post;
+	u8 d_ij_between_rs;
+
+	double zeta_ij;
+	double zeta_ji;
+	t_3dvec dzeta_ij;
+	t_3dvec dzeta_ji;
+} t_tersoff_exchange;
+
+/* tersoff mult (2!) potential parameters */
+typedef struct s_tersoff_mult_params {
+	double S[2];		/* tersoff cutoff radii */
+	double S2[2];		/* tersoff cutoff radii squared */
+	double R[2];		/* tersoff cutoff radii */
+	double Smixed;		/* mixed S radius */
+	double S2mixed;		/* mixed S radius squared */
+	double Rmixed;		/* mixed R radius */
+	double A[2];		/* factor of tersoff attractive part */
+	double B[2];		/* factor of tersoff repulsive part */
+	double Amixed;		/* mixed A factor */
+	double Bmixed;		/* mixed B factor */
+	double lambda[2];	/* tersoff lambda */
+	double lambda_m;	/* mixed lambda */
+	double mu[2];		/* tersoff mu */
+	double mu_m;		/* mixed mu */
+
+	double chi;
+
+	double beta[2];
+	double n[2];
+	double c[2];
+	double d[2];
+	double h[2];
+
+	t_tersoff_exchange exchange;	/* exchange between 2bp and 3bp calc */
+} t_tersoff_mult_params;
+
+/* function prototypes */
+int tersoff_mult_complete_params(t_tersoff_mult_params *p);
+int tersoff_mult_1bp(t_moldyn *moldyn,t_atom *ai);
+int tersoff_mult_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
+int tersoff_mult_post_2bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,u8 bc);
+int tersoff_mult_3bp(t_moldyn *moldyn,t_atom *ai,t_atom *aj,t_atom *ak,u8 bc);
+
+#endif
diff --git a/report/report.h b/report/report.h
index 4fe42f7..bd4ce88 100644
--- a/report/report.h
+++ b/report/report.h
@@ -87,10 +87,10 @@ set xtic auto \n\
 set ytic auto \n\
 set title 'Pressure vs. time' \n\
 set xlabel 'Time [fs]' \n\
-set ylabel 'Pressure [atm]' \n\
+set ylabel 'Pressure [bar]' \n\
 set terminal postscript eps enhanced color solid lw 1 'Helvetica' 14 \n\
 set output 'pressure.eps' \n\
-plot \"pressure\" using 1:2 title 'Pressure' with lines \
+plot \"pressure\" using 1:2 title 'P' with lines , \"pressure\" using 1:3 title '<P>' with lines , \"pressure\" using 1:4 title 'P (global virial)' with lines , \"pressure\" using 1:5 title '<P (global virial)>' with lines \
 ";
 
 static char temperature_plot_script[]="\
@@ -104,7 +104,7 @@ set xlabel 'Time [fs]' \n\
 set ylabel 'Temperature [K]' \n\
 set terminal postscript eps enhanced color solid lw 1 'Helvetica' 14 \n\
 set output 'temperature.eps' \n\
-plot \"temperature\" using 1:2 title 'Temperature' with lines \
+plot \"temperature\" using 1:2 title 'T' with lines , \"temperature\" using 1:3 title '<T>' with lines \
 ";
 
 #endif
diff --git a/sic.c b/sic.c
index 682d89e..a78f3a0 100644
--- a/sic.c
+++ b/sic.c
@@ -14,9 +14,10 @@
 #include "potentials/harmonic_oscillator.h"
 #include "potentials/lennard_jones.h"
 #include "potentials/tersoff.h"
+//#include "potentials/tersoff_orig.h"
 
-#define INJECT		20
-#define NR_ATOMS	20	
+#define INJECT		1
+#define NR_ATOMS	4
 
 int hook(void *moldyn,void *hook_params) {
 
@@ -97,8 +98,13 @@ int main(int argc,char **argv) {
 	/* choose potential */
 	set_potential1b(&md,tersoff_mult_1bp);
 	set_potential2b(&md,tersoff_mult_2bp);
-	set_potential2b_post(&md,tersoff_mult_post_2bp);
-	set_potential3b(&md,tersoff_mult_3bp);
+	//set_potential3b_j1(&md,tersoff_mult_2bp);
+	//set_potential3b_k1(&md,tersoff_mult_3bp);
+	//set_potential3b_j3(&md,tersoff_mult_post_2bp);
+	set_potential3b_j1(&md,tersoff_mult_3bp_j1);
+	set_potential3b_k1(&md,tersoff_mult_3bp_k1);
+	set_potential3b_j2(&md,tersoff_mult_3bp_j2);
+	set_potential3b_k2(&md,tersoff_mult_3bp_k2);
 	//set_potential2b(&md,lennard_jones);
 	//set_potential2b(&md,harmonic_oscillator);
 	set_potential_params(&md,&tp);
@@ -198,7 +204,7 @@ int main(int argc,char **argv) {
 
 	/* set temperature & pressure */
 	set_temperature(&md,atof(argv[2])+273.0);
-	set_pressure(&md,ATM);
+	set_pressure(&md,BAR);
 
 	/* set p/t scaling */
 	//set_pt_scale(&md,P_SCALE_BERENDSEN,0.001,
@@ -211,14 +217,14 @@ int main(int argc,char **argv) {
 
 	/* create the simulation schedule */
 	/* initial configuration */
-	moldyn_add_schedule(&md,500,1.0);
+	moldyn_add_schedule(&md,10000,1.0);
 	/* adding atoms */
-	for(inject=0;inject<INJECT;inject++) {
-		/* injecting atom and run with enabled t scaling */
-		moldyn_add_schedule(&md,400,1.0);
-		/* continue running with disabled t scaling */
-		moldyn_add_schedule(&md,100,1.0);
-	}
+	//for(inject=0;inject<INJECT;inject++) {
+	//	/* injecting atom and run with enabled t scaling */
+	//	moldyn_add_schedule(&md,900,1.0);
+	//	/* continue running with disabled t scaling */
+	//	moldyn_add_schedule(&md,1100,1.0);
+	//}
 
 	/* schedule hook function */
 	moldyn_set_schedule_hook(&md,&hook,NULL);
@@ -226,9 +232,9 @@ int main(int argc,char **argv) {
 	/* activate logging */
 	moldyn_set_log_dir(&md,argv[1]);
 	moldyn_set_report(&md,"Frank Zirkelbach","Test 1");
-	moldyn_set_log(&md,LOG_TOTAL_ENERGY,10);
-	moldyn_set_log(&md,LOG_TEMPERATURE,10);
-	moldyn_set_log(&md,LOG_PRESSURE,10);
+	moldyn_set_log(&md,LOG_TOTAL_ENERGY,1);
+	moldyn_set_log(&md,LOG_TEMPERATURE,1);
+	moldyn_set_log(&md,LOG_PRESSURE,1);
 	moldyn_set_log(&md,VISUAL_STEP,100);
 	moldyn_set_log(&md,SAVE_STEP,100);
 	moldyn_set_log(&md,CREATE_REPORT,0);