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/* -*- c++ -*- ----------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
Copyright (2003) Sandia Corporation. Under the terms of Contract
DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
certain rights in this software. This software is distributed under
the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
#ifdef PAIR_CLASS
PairStyle(tersoff/mod,PairTersoffMOD)
#else
#ifndef LMP_PAIR_TERSOFF_MOD_H
#define LMP_PAIR_TERSOFF_MOD_H
#include "pair_tersoff.h"
#include <cmath>
namespace LAMMPS_NS {
class PairTersoffMOD : public PairTersoff {
public:
PairTersoffMOD(class LAMMPS *);
~PairTersoffMOD() {}
protected:
virtual void read_file(char *);
virtual void setup_params();
double zeta(Param *, double, double, double *, double *);
double ters_fc(double, Param *);
double ters_fc_d(double, Param *);
double ters_bij(double, Param *);
double ters_bij_d(double, Param *);
void ters_zetaterm_d(double, double *, double, double *, double,
double *, double *, double *, Param *);
// inlined functions for efficiency
// these replace but do not override versions in PairTersoff
// since overriding virtual inlined functions is best avoided
inline double ters_gijk_mod(const double costheta,
const Param * const param) const {
const double ters_c1 = param->c1;
const double ters_c2 = param->c2;
const double ters_c3 = param->c3;
const double ters_c4 = param->c4;
const double ters_c5 = param->c5;
const double tmp_h = (param->h - costheta)*(param->h - costheta);
return ters_c1 + (ters_c2*tmp_h/(ters_c3 + tmp_h)) *
(1.0 + ters_c4*exp(-ters_c5*tmp_h));
}
inline double ters_gijk_d_mod(const double costheta,
const Param * const param) const {
const double ters_c2 = param->c2;
const double ters_c3 = param->c3;
const double ters_c4 = param->c4;
const double ters_c5 = param->c5;
const double tmp_h = (param->h - costheta)*(param->h - costheta);
const double g1 = (param->h - costheta)/(ters_c3 + tmp_h);
const double g2 = exp(-ters_c5*tmp_h);
return -2.0*ters_c2*g1*((1 + ters_c4*g2)*(1 + g1*(costheta - param->h)) -
tmp_h*ters_c4*ters_c5*g2);
}
};
}
#endif
#endif
/* ERROR/WARNING messages:
E: Cannot open Tersoff potential file %s
The specified potential file cannot be opened. Check that the path
and name are correct.
E: Incorrect format in Tersoff potential file
Incorrect number of words per line in the potential file.
E: Illegal Tersoff parameter
One or more of the coefficients defined in the potential file is
invalid.
E: Potential file has duplicate entry
The potential file has more than one entry for the same element.
E: Potential file is missing an entry
The potential file does not have a needed entry.
*/