AzizPotential Class Reference

Computes the value of the semi-empircal Aziz potential that is known to be accurate for He-4. More...

#include <potential.h>

Inheritance diagram for AzizPotential:

Collaboration diagram for AzizPotential:

Public Member Functions
	AzizPotential (const Container *)
	Constructor. More...
	~AzizPotential ()
	Destructor.
double	V (const dVec &)
	Return the aziz potential for separation r using a lookup table.
dVec	gradV (const dVec &)
	Return the gradient of aziz potential for separation r using a lookup table.
double	grad2V (const dVec &)
	Return the Laplacian of aziz potential for separation r using a lookup table.
Public Member Functions inherited from PotentialBase
	PotentialBase ()
	Constructor.
virtual	~PotentialBase ()
	Destructor.
virtual double	V (const dVec &, const dVec &)
	The effective potential for the pair product approximation.
virtual double	dVdlambda (const dVec &, const dVec &)
	The derivative of the effective potential with respect to lambda and tau.
virtual double	dVdtau (const dVec &, const dVec &)
virtual Array< dVec, 1 >	initialConfig (const Container *, MTRand &, const int)
	Default Initial configuration of particles. More...
void	output (const double)
	A debug method that output's the potential to a supplied separation. More...
virtual Array< double, 1 >	getExcLen ()
	Array to hold data elements. More...
Public Member Functions inherited from TabulatedPotential
	TabulatedPotential ()
	Constructor.
virtual	~TabulatedPotential ()
	Destructor.

Additional Inherited Members
Data Fields inherited from PotentialBase
double	tailV
	Tail correction factor.
Protected Member Functions inherited from PotentialBase
double	deltaSeparation (double sep1, double sep2) const
	Return the minimum image difference for 1D separations.
Protected Member Functions inherited from TabulatedPotential
void	initLookupTable (const double, const double)
	Given a discretization factor and the system size, create and fill the lookup tables for the potential and its derivative.
virtual double	newtonGregory (const Array< double, 1 > &, const TinyVector< double, 2 > &, const double)
	Use the Newton-Gregory forward difference method to do a 2-point lookup on the potential table. More...
virtual double	direct (const Array< double, 1 > &, const TinyVector< double, 2 > &, const double)
	Use a direct lookup for the potential table. More...
Protected Attributes inherited from TabulatedPotential
Array< double, 1 >	lookupV
	A potential lookup table.
Array< double, 1 >	lookupdVdr
	A lookup table for dVint/dr.
Array< double, 1 >	lookupd2Vdr2
	A lookup table for d2Vint/dr2.
double	dr
	The discretization for the lookup table.
int	tableLength
	The number of elements in the lookup table.
TinyVector< double, 2 >	extV
	Extremal value of V.
TinyVector< double, 2 >	extdVdr
	Extremal value of dV/dr.
TinyVector< double, 2 >	extd2Vdr2
	Extremal value of d2V/dr2.

Detailed Description

Computes the value of the semi-empircal Aziz potential that is known to be accurate for He-4.

Definition at line 678 of file potential.h.

Constructor & Destructor Documentation

AzizPotential()

AzizPotential::AzizPotential

(

const Container *

_boxPtr

)

Constructor.

Create the Aziz interaction potential. We use the standard 1979 values.

See also

R.A. Aziz et al. J. Chem. Phys. 70, 4330 (1979).

Definition at line 1475 of file potential.cpp.

                                                     : PotentialBase(), TabulatedPotential()
{
    /* Define all variables for the Aziz potential */
    /* R.A. Aziz et al. J. Chem. Phys. 70, 4330 (1979) */
    rm      = 2.9673;   // A
    A       = 0.5448504E6; 
    epsilon = 10.8;     // K
    alpha   = 13.353384; 
    D       = 1.241314; 
    C6      = 1.3732412;
    C8      = 0.4253785;
    C10     = 0.1781;
 
    /* The extremal values are all zero here */
    extV = 0.0;
    extdVdr = 0.0;
    extd2Vdr2 = 0.0;
 
    /* We take the maximum possible separation */
    double L = _boxPtr->maxSep;
 
    /* Create the potential lookup tables */
    // initLookupTable(0.00005*rm,L);
    initLookupTable((1.0E-6)*rm,L);
 
    /* Now we compute the tail correction */
    double rmoL = rm / L;
    double rm3 = rm*rm*rm;
    double t1 = A*exp(-alpha*L/(2.0*rm))*rm*(8.0*rm*rm + 4.0*L*rm * alpha + L*L*alpha*alpha)
        / (4.0*alpha*alpha*alpha);
    double t2 = 8.0*C6*pow(rmoL,3.0)/3.0;
    double t3 = 32.0*C8*pow(rmoL,5.0)/5.0;
    double t4 = 128.0*C10*pow(rmoL,7.0)/7.0;
    
    tailV = 2.0*M_PI*epsilon*(t1 - rm3*(t2+t3+t4));
}

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The documentation for this class was generated from the following files:

• include/potential.h
• src/potential.cpp