potentialDict 4.24 KB
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/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  1.3                                   |
|   \\  /    A nd           | Web:      http://www.openfoam.org               |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/

FoamFile
{
    version         2.0;
    format          ascii;

    root            "";
    case            "";
    instance        "";
    local           "";

    class           dictionary;
    object          potentials;
}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

// Subdictionaries specifying types of intermolecular potential.
// Sub-sub dictionaries specify the potentials themselves.

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// Removal order

// This is the order in which to remove overlapping pairs if more than one
// type of molecule is present.  The most valuable molecule type is at the
// right hand end, the molecule that will be removed 1st is 1st on the list.
// Not all types need to be present, a molecule that is not present is
// automatically less valuable than any on the list.  For molecules of the
// same type there is no control over which is removed.

removalOrder        1 (Ar);

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// Pair potentials

// If there are r different type of molecules, and a pair force is required
// between all combinations, then there are C = r(r+1)/2 combinations,
// i.e. for r = {1,2,3,4}, C = {1,3,6,10} (sum of triangular numbers).

// Pair potentials are specified by the combinaition of their ids,
// for MOLA and MOLB, "MOLA-MOLB" OR "MOLB-MOLA" is acceptable
// (strictly OR, both or neither will thrown an error)

pair
{
    Ar-Ar
    {
        pairPotential   maitlandSmith;
        rCut            1.0e-9;
        rMin            0.15e-9;
        dr              5e-14;
        maitlandSmithCoeffs
        {
            m           13.0;
            gamma       7.5;
            rm          0.3756e-9;
            epsilon     1.990108438e-21;
        }
        energyScalingFunction   doubleSigmoid;
        doubleSigmoidCoeffs
        {
            shift1      0.9e-9;
            scale1      0.3e11;
            shift2      0.97e-9;
            scale2      1.2e11;
        }
        writeTables     yes;
    }

    Ar-Ne
    {
        pairPotential   maitlandSmith;
        rCut            0.9e-9;
        rMin            0.1e-9;
        dr              5e-14;
        maitlandSmithCoeffs
        {
            m               13.0;
            gamma           4;
            rm              0.348e-9;
            epsilon         8.765026657e-22;
        }
        energyScalingFunction   shiftedForce;
        writeTables     yes;
    }

    Ne-Ne
    {
        pairPotential   maitlandSmith;
        rCut            0.8e-9;
        rMin            0.1e-9;
        dr              5e-14;
        maitlandSmithCoeffs
        {
            m               13.0;
            gamma           5;
            rm              0.30739e-9;
            epsilon         5.813260729e-22;
        }
        energyScalingFunction   shiftedForce;
        writeTables     yes;
    }
}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// Tethering Potentials

tether
{
    Ar
    {
        tetherPotential restrainedHarmonicSpring;
        restrainedHarmonicSpringCoeffs
        {
            springConstant  0.0277;
            rR              1.2e-9;
        }
    }

    Ne
    {
        tetherPotential harmonicSpring;
        harmonicSpringCoeffs
        {
            springConstant  0.0277;
        }
    }
}

// ************************************************************************* //

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// External Forces

// Bulk external forces (namely gravity) will be specified as forces rather
// than potentials to allow their direction to be controlled.

external
{
    gravity             (0 0 0);
}