sic.c

   1 /*
   2  * sic.c - investigation of the sic precipitation process of silicon carbide
   3  *
   4  * author: Frank Zirkelbach <frank.zirkelbach@physik.uni-augsburg.de>
   5  *
   6  */
   7
   8 #include <math.h>
   9
  10 #include "moldyn.h"
  11
  12 #include "posic.h"
  13
  14 int hook(void *moldyn,void *hook_params) {
  15
  16         t_moldyn *md;
  17
  18         md=moldyn;
  19
  20         /* switch to direct scaling in first hook */
  21         if(md->schedule.count==0)
  22                 set_pt_scale(md,0,0,T_SCALE_BERENDSEN,100.0);
  23         /* switch off temp scaling in second hook */
  24         if(md->schedule.count==1)
  25                 set_pt_scale(md,0,0,0,0);
  26
  27
  28         //set_temperature(md,md->t_ref-100.0);
  29
  30
  31         return 0;
  32 }
  33
  34 int main(int argc,char **argv) {
  35
  36         /* check argv */
  37         if(argc!=3) {
  38                 printf("[sic] usage: %s <logdir> <temperatur>\n",argv[0]);
  39                 return -1;
  40         }
  41
  42         /* main moldyn structure */
  43         t_moldyn md;
  44
  45         /* potential parameters */
  46         t_lj_params lj;
  47         t_ho_params ho;
  48         t_tersoff_mult_params tp;
  49
  50         /* testing location & velocity vector */
  51         t_3dvec r,v;
  52
  53         /* initialize moldyn */
  54         moldyn_init(&md,argc,argv);
  55
  56         /* choose integration algorithm */
  57         set_int_alg(&md,MOLDYN_INTEGRATE_VERLET);
  58
  59         /* choose potential */
  60         //set_potential1b(&md,tersoff_mult_1bp,&tp);
  61         //set_potential2b(&md,tersoff_mult_2bp,&tp);
  62         //set_potential2b_post(&md,tersoff_mult_post_2bp,&tp);
  63         //set_potential3b(&md,tersoff_mult_3bp,&tp);
  64         set_potential2b(&md,lennard_jones,&lj);
  65         //set_potential2b(&md,harmonic_oscillator,&ho);
  66
  67         /* cutoff radius */
  68         //set_cutoff(&md,TM_S_SI);
  69         set_cutoff(&md,2*LC_SI);
  70
  71         /*
  72          * potential parameters
  73          */
  74
  75         /* lennard jones */
  76         lj.sigma6=LJ_SIGMA_SI*LJ_SIGMA_SI*LJ_SIGMA_SI;
  77         lj.sigma6*=lj.sigma6;
  78         lj.sigma12=lj.sigma6*lj.sigma6;
  79         lj.epsilon4=4.0*LJ_EPSILON_SI;
  80         lj.uc=lj.epsilon4*(lj.sigma12/pow(md.cutoff,12.0)-lj.sigma6/pow(md.cutoff,6));
  81
  82         /* harmonic oscillator */
  83         ho.equilibrium_distance=0.25*sqrt(3.0)*LC_SI;
  84         ho.spring_constant=.1;
  85
  86         /*
  87          * tersoff mult potential parameters for SiC
  88          */
  89         tp.S[0]=TM_S_SI;
  90         tp.R[0]=TM_R_SI;
  91         tp.A[0]=TM_A_SI;
  92         tp.B[0]=TM_B_SI;
  93         tp.lambda[0]=TM_LAMBDA_SI;
  94         tp.mu[0]=TM_MU_SI;
  95         tp.beta[0]=TM_BETA_SI;
  96         tp.n[0]=TM_N_SI;
  97         tp.c[0]=TM_C_SI;
  98         tp.d[0]=TM_D_SI;
  99         tp.h[0]=TM_H_SI;
 100
 101         tp.S[1]=TM_S_C;
 102         tp.R[1]=TM_R_C;
 103         tp.A[1]=TM_A_C;
 104         tp.B[1]=TM_B_C;
 105         tp.lambda[1]=TM_LAMBDA_C;
 106         tp.mu[1]=TM_MU_C;
 107         tp.beta[1]=TM_BETA_C;
 108         tp.n[1]=TM_N_C;
 109         tp.c[1]=TM_C_C;
 110         tp.d[1]=TM_D_C;
 111         tp.h[1]=TM_H_C;
 112
 113         tp.chi=TM_CHI_SIC;
 114
 115         tersoff_mult_complete_params(&tp);
 116
 117         /* set (initial) dimensions of simulation volume */
 118         set_dim(&md,6*LC_SI,6*LC_SI,6*LC_SI,TRUE);
 119
 120         /* set periodic boundary conditions in all directions */
 121         set_pbc(&md,TRUE,TRUE,TRUE);
 122
 123         /* create the lattice / place atoms */
 124         create_lattice(&md,DIAMOND,LC_SI,SI,M_SI,
 125         //               ATOM_ATTR_1BP|ATOM_ATTR_2BP|ATOM_ATTR_3BP|ATOM_ATTR_HB,
 126                        ATOM_ATTR_2BP|ATOM_ATTR_HB,
 127                        0,6,6,6);
 128         moldyn_bc_check(&md);
 129
 130         /* testing configuration */
 131         //r.x=0.28*sqrt(3)*LC_SI/2;     v.x=0;
 132         //r.x=1.75*LC_SI;       v.x=-0.01;
 133         //r.y=0;                v.y=0;
 134         //r.z=0;                v.z=0;
 135         //add_atom(&md,SI,M_SI,0,
 136         //           ATOM_ATTR_1BP|ATOM_ATTR_2BP|ATOM_ATTR_3BP|ATOM_ATTR_HB,
 137         //           ATOM_ATTR_2BP|ATOM_ATTR_HB,
 138         //           &r,&v);
 139         //r.x=-r.x;     v.x=-v.x;
 140         //r.y=0;                v.y=0;
 141         //r.z=0;                v.z=0;
 142         //add_atom(&md,SI,M_SI,0,
 143         //           ATOM_ATTR_1BP|ATOM_ATTR_2BP|ATOM_ATTR_3BP|ATOM_ATTR_HB,
 144         //           ATOM_ATTR_2BP|ATOM_ATTR_HB,
 145         //           &r,&v);
 146
 147         /* setting a nearest neighbour distance for the moldyn checks */
 148         set_nn_dist(&md,0.25*sqrt(3.0)*LC_SI); /* diamond ! */
 149
 150         /* set temperature */
 151         //set_temperature(&md,273.0+1410.0);
 152         //set_temperature(&md,273.0+450.0);
 153         //set_temperature(&md,273.0);
 154         //set_temperature(&md,1.0);
 155         //set_temperature(&md,0.0);
 156         set_temperature(&md,atof(argv[2])+273.0);
 157
 158         /* set pressure */
 159         set_pressure(&md,ATM);
 160
 161         /* set p/t scaling */
 162         //set_pt_scale(&md,P_SCALE_BERENDSEN,100.0,
 163         //                 T_SCALE_BERENDSEN,100.0);
 164         set_pt_scale(&md,0,0,T_SCALE_DIRECT,1.0);
 165         //set_pt_scale(&md,P_SCALE_BERENDSEN,100.0,0,0);
 166
 167         /* initial thermal fluctuations of particles (in equilibrium) */
 168         thermal_init(&md,TRUE);
 169
 170         /* create the simulation schedule */
 171         moldyn_add_schedule(&md,1001,3.0);
 172         moldyn_add_schedule(&md,501,1.0);
 173         moldyn_add_schedule(&md,501,1.0);
 174
 175         /* schedule hook function */
 176         moldyn_set_schedule_hook(&md,&hook,NULL);
 177
 178         /* activate logging */
 179         moldyn_set_log_dir(&md,argv[1]);
 180         moldyn_set_log(&md,LOG_TOTAL_ENERGY,5);
 181         moldyn_set_log(&md,VISUAL_STEP,50);
 182
 183         /*
 184          * let's do the actual md algorithm now
 185          *
 186          * integration of newtons equations
 187          */
 188         moldyn_integrate(&md);
 189
 190         /* close */
 191         moldyn_shutdown(&md);
 192
 193         return 0;
 194 }
 195