FreeFOAM The Cross-Platform CFD Toolkit
lennardJones.C
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3  \\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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5  \\ / A nd | Copyright (C) 2008-2010 OpenCFD Ltd.
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24 \*---------------------------------------------------------------------------*/
25 
26 #include "lennardJones.H"
28 
29 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
30 
31 namespace Foam
32 {
33 namespace pairPotentials
34 {
35 
36 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
37 
38 defineTypeNameAndDebug(lennardJones, 0);
39 
41 (
42  pairPotential,
43  lennardJones,
44  dictionary
45 );
46 
47 
48 // * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
49 
51 (
52  const word& name,
53  const dictionary& pairPotentialProperties
54 )
55 :
56  pairPotential(name, pairPotentialProperties),
57  lennardJonesCoeffs_(pairPotentialProperties.subDict(typeName + "Coeffs")),
58  sigma_(readScalar(lennardJonesCoeffs_.lookup("sigma"))),
59  epsilon_(readScalar(lennardJonesCoeffs_.lookup("epsilon")))
60 {
61  setLookupTables();
62 }
63 
64 
65 // * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
66 
67 scalar lennardJones::unscaledEnergy(const scalar r) const
68 {
69  // (rIJ/sigma)^-2
70  scalar ir2 = (sigma_/r)*(sigma_/r);
71 
72  // (rIJ/sigma)^-6
73  scalar ir6 = ir2*ir2*ir2;
74 
75  return 4.0 * epsilon_*(ir6*(ir6 - 1.0));
76 }
77 
78 
79 bool lennardJones::read(const dictionary& pairPotentialProperties)
80 {
81  pairPotential::read(pairPotentialProperties);
82 
83  lennardJonesCoeffs_ = pairPotentialProperties.subDict(typeName + "Coeffs");
84 
85  lennardJonesCoeffs_.lookup("sigma") >> sigma_;
86  lennardJonesCoeffs_.lookup("epsilon") >> epsilon_;
87 
88  return true;
89 }
90 
91 
92 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
93 
94 } // End namespace pairPotentials
95 } // End namespace Foam
96 
97 // ************************ vim: set sw=4 sts=4 et: ************************ //