tutorials/gnemdFoam/constrictedChannel/system/potentialDict

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   3 | \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
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   7 \*---------------------------------------------------------------------------*/
   8 FoamFile
   9 {
  10     version     2.0;
  11     format      ascii;
  12     class       dictionary;
  13     object      potentials;
  14 }
  15 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
  16
  17 // Subdictionaries specifying types of intermolecular potential.
  18 // Sub-sub dictionaries specify the potentials themselves.
  19
  20 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
  21 // Removal order
  22
  23 // This is the order in which to remove overlapping pairs if more than one
  24 // type of molecule is present.  The most valuable molecule type is at the
  25 // right hand end, the molecule that will be removed 1st is 1st on the list.
  26 // Not all types need to be present, a molecule that is not present is
  27 // automatically less valuable than any on the list.  For molecules of the
  28 // same type there is no control over which is removed.
  29
  30 removalOrder        2 (Ne Ar);
  31
  32 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
  33 // Pair potentials
  34
  35 // If there are r different type of molecules, and a pair force is required
  36 // between all combinations, then there are C = r(r+1)/2 combinations,
  37 // i.e. for r = {1,2,3,4}, C = {1,3,6,10} (sum of triangular numbers).
  38
  39 // Pair potentials are specified by the combinaition of their ids,
  40 // for MOLA and MOLB, "MOLA-MOLB" OR "MOLB-MOLA" is acceptable
  41 // (strictly OR, both or neither will thrown an error)
  42
  43 pair
  44 {
  45     Ar-Ar
  46     {
  47         pairPotential   maitlandSmith;
  48         rCut            1.0e-9;
  49         rMin            0.15e-9;
  50         dr              5e-14;
  51         maitlandSmithCoeffs
  52         {
  53             m           13.0;
  54             gamma       7.5;
  55             rm          0.3756e-9;
  56             epsilon     1.990108438e-21;
  57         }
  58         energyScalingFunction   doubleSigmoid;
  59         doubleSigmoidCoeffs
  60         {
  61             shift1      0.9e-9;
  62             scale1      0.3e11;
  63             shift2      0.97e-9;
  64             scale2      1.2e11;
  65         }
  66         writeTables     yes;
  67     }
  68
  69     Ar-Ne
  70     {
  71         pairPotential   maitlandSmith;
  72         rCut            0.9e-9;
  73         rMin            0.1e-9;
  74         dr              5e-14;
  75         maitlandSmithCoeffs
  76         {
  77             m               13.0;
  78             gamma           4;
  79             rm              0.348e-9;
  80             epsilon         8.765026657e-22;
  81         }
  82         energyScalingFunction   shiftedForce;
  83         writeTables     yes;
  84     }
  85
  86     Ne-Ne
  87     {
  88         pairPotential   maitlandSmith;
  89         rCut            0.8e-9;
  90         rMin            0.1e-9;
  91         dr              5e-14;
  92         maitlandSmithCoeffs
  93         {
  94             m               13.0;
  95             gamma           5;
  96             rm              0.30739e-9;
  97             epsilon         5.813260729e-22;
  98         }
  99         energyScalingFunction   shiftedForce;
 100         writeTables     yes;
 101     }
 102 }
 103
 104 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 105 // Tethering Potentials
 106
 107 tether
 108 {
 109     Ar
 110     {
 111         tetherPotential restrainedHarmonicSpring;
 112         restrainedHarmonicSpringCoeffs
 113         {
 114             springConstant  0.1;
 115             rR              1.2e-9;
 116         }
 117     }
 118 }
 119
 120 // ************************************************************************* //
 121
 122 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 123 // External Forces
 124
 125 // Bulk external forces (namely gravity) will be specified as forces rather
 126 // than potentials to allow their direction to be controlled.
 127
 128 external
 129 {
 130     gravity             (0 0 0);
 131 }