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lammps/tools/eam_generate/Cu_Mishin1.c
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Cu_Mishin1.c
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#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdarg.h>
#include <string.h>
#define rc 5.50679// A
#define h 0.50037// A
#define E1 2.01458*1e2//eV
#define E2 6.59288*1e-3//eV
#define r01 0.83591//A
#define r02 4.46867//A
#define a1 2.97758//1/A
#define a2 1.54927//1/A
#define d 0.86225*1e-2//A
#define rs1 2.24//A
#define rs2 1.8//A
#define rs3 1.2//A
#define S1 4.//eV/A^4
#define S2 40.//eV/A^4
#define S3 1.15*1e3//eV/A^4
#define a 3.80362
#define r03 -2.19885//A
#define r04 -2.61984*1e2//A
#define b1 0.17394//A^-2
#define b2 5.35661*1e2//1/A
#define F0 -2.28235//eV
#define F2 1.35535//eV
#define q1 -1.27775//eV
#define q2 -0.86074//eV
#define q3 1.78804//eV
#define q4 2.97571//eV
#define Q1 0.4
#define Q2 0.3
#define EOK 0
#define ERROR -1
double M (double r, double r0, double alpha) {
return exp (-2.*alpha*(r-r0)) - 2.*exp (-alpha*(r-r0));
}
double psi (double x) {
if (x >= 0.) return 0.;
else return pow (x, 4.) / (1.+pow (x, 4.) );
}
double H (double x) {
if (x >= 0) return 1.;
else return 0.;
}
double V (double r) {
return ( E1*M(r,r01,a1) + E2*M(r,r02,a2) + d ) * psi ( (r-rc)/h ) -
H (rs1-r)*S1*pow (rs1-r, 4.) -
H (rs2-r)*S2*pow (rs2-r, 4.) -
H (rs3-r)*S3*pow (rs3-r, 4.);
}
double rho (double r) {
return ( a*exp (-b1*pow (r-r03, 2.)) + exp (-b2*(r-r04)) ) * psi ( (r-rc)/h );
}
double F (double rho_) {
if (rho_ < 1.)
return F0 + .5*F2*pow (rho_-1., 2.)
+ q1*pow (rho_-1.,3.)
+ q2*pow (rho_-1.,4.)
+ q3*pow (rho_-1.,5.)
+ q4*pow (rho_-1.,6.);
else if (rho_ > 1.)
return ( F0 + .5*F2*pow (rho_-1., 2.) + q1*pow (rho_-1., 3.) + Q1*pow (rho_-1., 4.)) /
( 1. + Q2*pow (rho_-1., 3.) );
else exit (ERROR);
}
int main (void) {
int Nr = 10001;
double rmax = 9.;
double dr = rmax/(double)Nr;
int Nrho = 10001;
double rhomax = rho (0.);
double drho = rhomax/(double)Nrho;
int atomic_number = 1;
double mass = 63.55;
double lattice_constant = 3.615;
char lattice_type[] = "FCC";
int i;
char LAMMPSFilename[] = "Cu_Mishin1.eam";
FILE *LAMMPSFile = fopen (LAMMPSFilename, "w");
if (!LAMMPSFile) exit (ERROR);
// Header for setfl format
fprintf (LAMMPSFile, \
"#-> LAMMPS Potential File in DYNAMO 86 setfl Format <-#\n"\
"# Mishin Cu EAM1 PRB(2001)63:224106\n"\
"# Implemented by G. Ziegenhain (2007) gerolf@ziegenhain.com \n"\
"%d Cu\n"\
"%d %20.20f %d %20.20f %20.20f\n"\
"%d %20.20f %20.20f %s\n",
atomic_number,
Nrho, drho, Nr, dr, rc,
atomic_number, mass, lattice_constant, lattice_type);
// Embedding function
for (i = 0; i < Nrho; i++)
fprintf (LAMMPSFile, "%20.20f\n", F ((double)i*drho));
// Density function
for (i = 0; i < Nr; i++)
fprintf (LAMMPSFile, "%20.20f\n", rho ((double)i*dr));
// Pair potential
for (i = 0; i < Nr; i++)
fprintf (LAMMPSFile, "%20.20f\n", V ((double)i*dr) * (double)i*dr);
fclose (LAMMPSFile);
return (EOK);
}
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