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ESPResSo
Extensible Simulation Package for Research on Soft Matter Systems
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buckingham.cpp
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20 */
21/** \file
22 *
23 * Implementation of \ref buckingham.hpp
24 */
25#include "buckingham.hpp"
26
27#ifdef BUCKINGHAM
29
30#include <stdexcept>
31
33 double d, double cutoff,
34 double discont, double shift)
35 : A{a}, B{b}, C{c}, D{d}, cut{cutoff}, discont{discont}, shift{shift} {
36 if (a < 0.) {
37 throw std::domain_error("Buckingham parameter 'a' has to be >= 0");
38 }
39 if (b < 0.) {
40 throw std::domain_error("Buckingham parameter 'b' has to be >= 0");
41 }
42 if (c < 0.) {
43 throw std::domain_error("Buckingham parameter 'c' has to be >= 0");
44 }
45 if (d < 0.) {
46 throw std::domain_error("Buckingham parameter 'd' has to be >= 0");
47 }
48 if (cutoff < 0.) {
49 throw std::domain_error("Buckingham parameter 'cutoff' has to be >= 0");
50 }
51
52 /* Replace the Buckingham potential for interatomic distance less
53 than or equal to discontinuity by a straight line (F1+F2*r) */
54 auto const F = buck_force_r(A, B, C, D, discont);
55 F1 = buck_energy_r(A, B, C, D, shift, discont) + discont * F;
56 F2 = -F;
57}
58
59#endif // BUCKINGHAM
Routines to calculate the Buckingham potential between particle pairs.
double buck_energy_r(double A, double B, double C, double D, double shift, double r)
Potential Energy due to a Buckingham potential between two particles at interatomic separation r grea...
double buck_force_r(double A, double B, double C, double D, double r)
Resultant Force due to a Buckingham potential between two particles at interatomic separation r great...
Various procedures concerning interactions between particles.
Buckingham_Parameters()=default