Package etomica.potential

Class P2WCA

java.lang.Object

etomica.potential.Potential

etomica.potential.Potential2

etomica.potential.Potential2SoftSpherical

etomica.potential.P2WCA

All Implemented Interfaces:

IPotential, IPotentialAtomic, Potential2Soft, Potential2Spherical, PotentialSoft

public class P2WCA
extends Potential2SoftSpherical

Weeks-Chandler-Andersen potential. Obtained by truncating the Lennard-Jones potential at the separation where it has its minimum, and shifting it upwards so the minimum is at zero energy. The resulting potential has a value and first derivative that is continuous at the point of truncation.

Field Summary

Fields inherited from class etomica.potential.Potential

space

Fields inherited from class etomica.potential.Potential2SoftSpherical

boundary, dr, gradient

Constructor Summary

Constructors

Constructor	Description
P2WCA(Space _space)	Constructs potential using default sigma and epsilon given by Default class.
P2WCA(Space _space, double sigma, double epsilon)

Method Summary

Modifier and Type	Method	Description
double	d2u(double r2)	The second derivative of the pair energy, times the square of the separation: r^2 d^2u/dr^2.
double	du(double r2)	The derivative r*du/dr.
double	getEpsilon()	Accessor method for the energy parameter
Dimension	getEpsilonDimension()
double	getRange()	Returns the range of the potential, which is the point of truncation.
double	getSigma()	Accessor method for the size parameter.
Dimension	getSigmaDimension()
void	setEpsilon(double eps)	Mutator method for the energy parameter
void	setSigma(double s)	Mutator method for Lennard-Jones size parameter.
double	u(double r2)	The energy u.
double	uInt(double rC)	Returns zero, since there is no long-range correction.

Methods inherited from interface etomica.potential.IPotential

nBody

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from class etomica.potential.Potential

nBody

Methods inherited from class etomica.potential.Potential2SoftSpherical

energy, gradient, gradient, hyperVirial, integral, setBox, virial

Constructor Detail

P2WCA

public P2WCA(Space _space)

Constructs potential using default sigma and epsilon given by Default class.

P2WCA

public P2WCA(Space _space,
             double sigma,
             double epsilon)

Method Detail

getRange

public double getRange()

Returns the range of the potential, which is the point of truncation. This is equal to 2^(1/6) * sigma.

Specified by:

getRange in interface IPotential

Overrides:

getRange in class Potential2SoftSpherical

u

public double u(double r2)

The energy u.

Parameters:

r2 - the square of the distance between the particles.

du

public double du(double r2)

The derivative r*du/dr.

Specified by:

du in interface Potential2Soft

Specified by:

du in class Potential2SoftSpherical

d2u

public double d2u(double r2)

The second derivative of the pair energy, times the square of the separation: r^2 d^2u/dr^2.

Specified by:

d2u in class Potential2SoftSpherical

uInt

public double uInt(double rC)

Returns zero, since there is no long-range correction.

Specified by:

uInt in class Potential2SoftSpherical

getSigma

public double getSigma()

Accessor method for the size parameter.

setSigma

public final void setSigma(double s)

Mutator method for Lennard-Jones size parameter. Does not adjust potential cutoff for change in sigma.

getSigmaDimension

public Dimension getSigmaDimension()

getEpsilon

public double getEpsilon()

Accessor method for the energy parameter

setEpsilon

public final void setEpsilon(double eps)

Mutator method for the energy parameter

getEpsilonDimension

public Dimension getEpsilonDimension()