BALL::CharmmImproperTorsion Class Reference
[CHARMM Force Field.]

Charmm improper torsion component. More...

#include <charmmImproperTorsion.h>

Inheritance diagram for BALL::CharmmImproperTorsion:

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List of all members.

Public Member Functions
Constructors and Destructors
	CharmmImproperTorsion ()
	Default constructor.
	CharmmImproperTorsion (ForceField &force_field)
	Constructor.
	CharmmImproperTorsion (const CharmmImproperTorsion &charmm_stretch)
	Copy constructor.
virtual	~CharmmImproperTorsion ()
	Destructor.
Setup Methods
virtual bool	setup () throw (Exception::TooManyErrors)
	Setup method.
Accessors
virtual double	updateEnergy ()
	Calculates and returns the component's energy.
virtual void	updateForces ()
	Calculates and returns the component's forces.

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Detailed Description

Charmm improper torsion component.

The CHARMM force field employs a harmonic out-of-plane potential for improper torsions. An imporper torsion is defined for four atoms A , B , C , and D where A is the central atom B , C , and D are bound to.

The out-of-plane-angle phi is defined as the angle between the planes defined by ABC and BCD . The improper torsion energy $E_{imp}$ is then defined as $ E_{imp} = k ( - )^2 $ where $k$ and $$ are constants read from the parameter section and depend on the atom types of A , B , C , and D .