Package etomica.potential

Class P2PenetrableSquareWell

java.lang.Object

etomica.potential.Potential

etomica.potential.Potential2

etomica.potential.Potential2HardSpherical

etomica.potential.P2PenetrableSquareWell

All Implemented Interfaces:

IPotential, IPotentialAtomic, Potential2Spherical, PotentialHard

public class P2PenetrableSquareWell
extends Potential2HardSpherical

Square-well potential with a penetrable core. Energy is epsilonCore if spheres overlap, is -epsilon if less than lambda*sigma and not overlapping, and is zero otherwise. Core diameter describes size of penetrable core; lambda is multiplier to get range of well. Suitable for use in space of any dimension. Can be used with negative value for epsilon to produce square-shoulder potential.

Field Summary

Fields

Modifier and Type	Field	Description
protected double	coreDiameterSquared
protected double	deltaEps
protected Vector	dv
protected double	epsilon
protected double	epsilonCore
protected boolean	ignoreOverlap
protected double	lambdaSquared
protected double	lastCollisionVirial
protected double	lastCollisionVirialr2
protected Tensor	lastCollisionVirialTensor
protected double	lastEnergyChange
protected double	wellDiameterSquared

Fields inherited from class etomica.potential.Potential

space

Fields inherited from class etomica.potential.Potential2HardSpherical

boundary, dr

Constructor Summary

Constructors

Constructor	Description
P2PenetrableSquareWell(Space space)
P2PenetrableSquareWell(Space space, double coreDiameter, double lambda, double epsilon, boolean ignoreOverlap)

Method Summary

Modifier and Type	Method	Description
void	bump(IAtomList pair, double falseTime)	Implements collision dynamics between two square-well atoms.
double	collisionTime(IAtomList pair, double falseTime)	Computes next time of collision of two square-well atoms, assuming free-flight kinematics.
double	energyChange()	returns change in potential energy due to the last collision
double	getCoreDiameter()	Accessor method for core diameter.
Dimension	getCoreDiameterDimension()
double	getEpsilon()	Accessor method for depth of well
double	getEpsilonCore()
Dimension	getEpsilonCoreDimension()
Dimension	getEpsilonDimension()
double	getLambda()	Accessor method for well-diameter multiplier.
Dimension	getLambdaDimension()
double	getRange()	Returns the range over which the potential applies.
double	lastCollisionVirial()	Value of the virial from the most recent collision.
Tensor	lastCollisionVirialTensor()	Value of the virial from the most recent collision, decomposed into it tensoral elements.
void	setCoreDiameter(double c)	Accessor method for core diameter.
void	setCoreDiameterSquared(double c2)
void	setEpsilon(double eps)	Mutator method for depth of well.
void	setEpsilonCore(double epsilsonCore)	Sets height of penetrable core.
void	setLambda(double lam)	Accessor method for well-diameter multiplier.
double	u(double r2)	Returns infinity if overlapping, -epsilon if otherwise less than well diameter, or zero if neither.

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.Potential2HardSpherical

energy, setBox

Field Detail

coreDiameterSquared

protected double coreDiameterSquared

wellDiameterSquared

protected double wellDiameterSquared

lambdaSquared

protected double lambdaSquared

epsilon

protected double epsilon

epsilonCore

protected double epsilonCore

deltaEps

protected double deltaEps

lastCollisionVirial

protected double lastCollisionVirial

lastCollisionVirialr2

protected double lastCollisionVirialr2

lastCollisionVirialTensor

protected Tensor lastCollisionVirialTensor

lastEnergyChange

protected double lastEnergyChange

dv

protected Vector dv

ignoreOverlap

protected final boolean ignoreOverlap

Constructor Detail

P2PenetrableSquareWell

public P2PenetrableSquareWell(Space space)

P2PenetrableSquareWell

public P2PenetrableSquareWell(Space space,
                              double coreDiameter,
                              double lambda,
                              double epsilon,
                              boolean ignoreOverlap)

Method Detail

getRange

public double getRange()

Description copied from interface: IPotential

Returns the range over which the potential applies. IAtoms with a greater separation do not interact.

Specified by:

getRange in interface IPotential

Specified by:

getRange in class Potential

bump

public void bump(IAtomList pair,
                 double falseTime)

Implements collision dynamics between two square-well atoms. Includes all possibilities involving collision of cores, and collision of wells both approaching and diverging

lastCollisionVirial

public double lastCollisionVirial()

Description copied from interface: PotentialHard

Value of the virial from the most recent collision.

Returns:

double virial value

lastCollisionVirialTensor

public Tensor lastCollisionVirialTensor()

Description copied from interface: PotentialHard

Value of the virial from the most recent collision, decomposed into it tensoral elements.

Returns:

Tensor

collisionTime

public double collisionTime(IAtomList pair,
                            double falseTime)

Computes next time of collision of two square-well atoms, assuming free-flight kinematics. Collision may occur when cores collides, or when wells first encounter each other on approach, or when they edge of the wells are reached as atoms diverge.

u

public double u(double r2)

Returns infinity if overlapping, -epsilon if otherwise less than well diameter, or zero if neither.

Specified by:

u in interface Potential2Spherical

Specified by:

u in class Potential2HardSpherical

Parameters:

r2 - the square of the distance between the particles.

energyChange

public double energyChange()

Description copied from interface: PotentialHard

returns change in potential energy due to the last collision

getCoreDiameter

public double getCoreDiameter()

Accessor method for core diameter.

setCoreDiameter

public void setCoreDiameter(double c)

Accessor method for core diameter. Well diameter is defined as a multiple (lambda) of this, and is updated when core diameter is changed

getCoreDiameterDimension

public Dimension getCoreDiameterDimension()

setCoreDiameterSquared

public void setCoreDiameterSquared(double c2)

getLambda

public double getLambda()

Accessor method for well-diameter multiplier.

setLambda

public void setLambda(double lam)

Accessor method for well-diameter multiplier. Well diameter is defined as this multiple of core diameter, and is updated when this is changed

getLambdaDimension

public Dimension getLambdaDimension()

getEpsilon

public double getEpsilon()

Accessor method for depth of well

setEpsilon

public void setEpsilon(double eps)

Mutator method for depth of well. Positive value corresponds to depth of the well, and a negative well energy.

getEpsilonDimension

public Dimension getEpsilonDimension()

getEpsilonCore

public double getEpsilonCore()

setEpsilonCore

public void setEpsilonCore(double epsilsonCore)

Sets height of penetrable core. Positive value corresponds to a positive height of the core energy.

getEpsilonCoreDimension

public Dimension getEpsilonCoreDimension()