parmed.topologyobjects.Angle

class parmed.topologyobjects.Angle(atom1, atom2, atom3, type=None)

A valence angle between 3 atoms separated by two covalent bonds.

Parameters

atom1Atom

An atom one end of the valence angle

atom2Atom

The atom in the middle of the valence angle bonded to both other atoms

atom3Atom

An atom on the other end of the valence angle to atom1

typeAngleType

The AngleType object containing the parameters for this angle

Notes

An Angle can contain bonds or atoms. A bond is contained if it exists between atoms 1 and 2 or atoms 2 and 3.

Examples

>>> a1, a2, a3 = Atom(), Atom(), Atom()
>>> angle = Angle(a1, a2, a3)
>>> Bond(a1, a2) in angle and Bond(a3, a2) in angle
True
>>> a1 in angle and a2 in angle and a3 in angle
True
>>> Bond(a1, a3) in angle # this is not part of the angle definition
False

Methods

delete()	Deletes this angle from the atoms that make it up.
energy()	Measures the current angle energy
measure()	Measures the current angle
uenergy()	Same as energy(), but with units
umeasure()	Same as measure(), but with units

__init__(atom1, atom2, atom3, type=None)

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__(atom1, atom2, atom3[, type])	Initialize self.
delete()	Deletes this angle from the atoms that make it up.
energy()	Measures the current angle energy
measure()	Measures the current angle
uenergy()	Same as energy(), but with units
umeasure()	Same as measure(), but with units