ESPResSo
Extensible Simulation Package for Research on Soft Matter Systems
Loading...
Searching...
No Matches
morse.hpp
Go to the documentation of this file.
1/*
2 * Copyright (C) 2010-2022 The ESPResSo project
3 * Copyright (C) 2002,2003,2004,2005,2006,2007,2008,2009,2010
4 * Max-Planck-Institute for Polymer Research, Theory Group
5 *
6 * This file is part of ESPResSo.
7 *
8 * ESPResSo is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or
11 * (at your option) any later version.
12 *
13 * ESPResSo is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21#ifndef CORE_NB_IA_MORSE_HPP
22#define CORE_NB_IA_MORSE_HPP
23
24/** \file
25 * Routines to calculate the Morse potential between particle pairs.
26 *
27 * Implementation in \ref morse.cpp.
28 */
29
30#include "config/config.hpp"
31
32#ifdef MORSE
33
35
36#include <utils/math/sqr.hpp>
37
38#include <cmath>
39
40/** Calculate Morse force factor */
41inline double morse_pair_force_factor(IA_parameters const &ia_params,
42 double dist) {
43 if (dist < ia_params.morse.cut) {
44 auto const add =
45 exp(-ia_params.morse.alpha * (dist - ia_params.morse.rmin));
46 return -ia_params.morse.eps * 2.0 * ia_params.morse.alpha *
47 (add - Utils::sqr(add)) / dist;
48 }
49 return 0.0;
50}
51
52/** Calculate Morse energy */
53inline double morse_pair_energy(IA_parameters const &ia_params, double dist) {
54 if (dist < ia_params.morse.cut) {
55 auto const add =
56 exp(-ia_params.morse.alpha * (dist - ia_params.morse.rmin));
57 return ia_params.morse.eps * (Utils::sqr(add) - 2 * add) -
58 ia_params.morse.rest;
59 }
60 return 0.0;
61}
62
63#endif // MORSE
64#endif
This file contains the defaults for ESPResSo.
double morse_pair_force_factor(IA_parameters const &ia_params, double dist)
Calculate Morse force factor.
Definition morse.hpp:41
double morse_pair_energy(IA_parameters const &ia_params, double dist)
Calculate Morse energy.
Definition morse.hpp:53
DEVICE_QUALIFIER constexpr T sqr(T x)
Calculates the SQuaRe of x.
Definition sqr.hpp:28
Various procedures concerning interactions between particles.
Parameters for non-bonded interactions.