Package etomica.potential

Class P3BondAngleDreiding

java.lang.Object

etomica.potential.Potential

etomica.potential.P3BondAngleDreiding

All Implemented Interfaces:

IPotential, IPotentialAtomic, PotentialSoft

public class P3BondAngleDreiding
extends Potential
implements PotentialSoft

Simple 3-body soft bond-angle for Dreiding potential * U(theta) = gamma * [ cos(theta) - cos(theta_e)]^2 where gamma is the potential's energy parameter theta_e is the equilibrium bond angle

Field Summary

Fields

Modifier and Type	Field	Description
protected Boundary	boundary
protected Vector	dr12
protected Vector	dr23
protected Vector[]	gradient

Fields inherited from class etomica.potential.Potential

space

Constructor Summary

Constructors

Constructor	Description
P3BondAngleDreiding(Space space, double thetaEq, double gamma)

Method Summary

Modifier and Type	Method	Description
double	energy(IAtomList atomSet)	Returns the interaction energy between the given atoms.
double	getAngle()	Returns the nominal bond angle (in radians)
double	getGamma()	Returns the characteristic energy of the potential
double	getRange()	Returns the range over which the potential applies.
Vector[]	gradient(IAtomList atoms)	Returns the gradient of the potential as it applies to each atom in the given AtomSet, indicating how the energy would change as the position of the first atom is varied.
Vector[]	gradient(IAtomList atomSet, Tensor pressureTensor)	Returns the same gradient as gradient(AtomSet) and also adds in the contribution of the AtomSet to the pressureTensor.
void	setAngle(double newAngle)	Sets the nominal bond angle (in radians)
void	setBox(Box box)	Informs the potential of the box on which it acts.
void	setGamma(double newGamma)	Sets the characteristic energy of the potential
double	virial(IAtomList atomSet)

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

Field Detail

dr12

protected final Vector dr12

dr23

protected final Vector dr23

gradient

protected final Vector[] gradient

boundary

protected Boundary boundary

Constructor Detail

P3BondAngleDreiding

public P3BondAngleDreiding(Space space,
                           double thetaEq,
                           double gamma)

Method Detail

virial

public double virial(IAtomList atomSet)

Specified by:

virial in interface PotentialSoft

gradient

public Vector[] gradient(IAtomList atomSet,
                         Tensor pressureTensor)

Description copied from interface: PotentialSoft

Returns the same gradient as gradient(AtomSet) and also adds in the contribution of the AtomSet to the pressureTensor. Their contribution is added to the given Tensor. This combined method exists for computational efficiency. Calculating the pressureTensor is generally trivial once the gradient is known but often requires intermediate information.

Specified by:

gradient in interface PotentialSoft

gradient

public Vector[] gradient(IAtomList atoms)

Description copied from interface: PotentialSoft

Returns the gradient of the potential as it applies to each atom in the given AtomSet, indicating how the energy would change as the position of the first atom is varied. The method is allowed to return an array of Vectors with fewer elements than the number of atoms in the AtomSet.

Specified by:

gradient in interface PotentialSoft

Returns:

setBox

public void setBox(Box box)

Description copied from class: Potential

Informs the potential of the box on which it acts. Typically this requires at least that it update the nearestImageTransformer of its coordinatePair (if it uses one), e.g.: cPair.setNearestImageTransformer(box.boundary());

Specified by:

setBox in interface IPotential

Specified by:

setBox in class Potential

energy

public double energy(IAtomList atomSet)

Description copied from class: Potential

Returns the interaction energy between the given atoms. There might be 0, 1, 2 or more atoms in the AtomSet.

Specified by:

energy in interface IPotentialAtomic

Specified by:

energy in class Potential

setAngle

public void setAngle(double newAngle)

Sets the nominal bond angle (in radians)

getAngle

public double getAngle()

Returns the nominal bond angle (in radians)

setGamma

public void setGamma(double newGamma)

Sets the characteristic energy of the potential

getGamma

public double getGamma()

Returns the characteristic energy of the potential

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