espressopp.interaction.DihedralHarmonic¶
The dihedral harmonic potential
\[U(\phi_{ijkl}) = 0.5K[\phi_{ijkl} - \phi_0)]^2\]
where the K is a constant, the angles should be provided in radians.
Reference: Gromacs Manual 4.6.1, section 4.2.11 (page 79-80), equation 4.60
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espressopp.interaction.
DihedralHarmonic
(K, phi0)¶ Parameters: - K (real) – (default: 0.0)
- phi0 (real) – (default: 0.0)
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espressopp.interaction.
FixedQuadrupleListDihedralHarmonic
(system, fql, potential)¶ Parameters: - system –
- fql –
- potential –
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espressopp.interaction.FixedQuadrupleListDihedralHarmonic.
getFixedQuadrupleList
()¶ Return type: A Python list of lists.
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espressopp.interaction.FixedQuadrupleListDihedralHarmonic.
setPotential
(potential)¶ Parameters: potential –
Example of usage
>>> # The following example shows how to add a torsional potential to particles 1,2,3,4
>>> fql = espressopp.FixedQuadrupleList(system.storage)
>>> fql.addQuadruples([(1,2,3,4)])
>>> #phi0 is in radians, IUPAC convention definition
>>> interaction = espressopp.interaction.FixedQuadrupleListDihedralHarmonic(system,fql,potential=espressopp.interaction.DihedralHarmonic(K=1.0,phi0=0.0))
>>> system.addInteraction(interaction)
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class
espressopp.interaction.DihedralHarmonic.
DihedralHarmonic
¶ The DihedralHarmonic potential.
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class
espressopp.interaction.DihedralHarmonic.
FixedQuadrupleListDihedralHarmonicLocal
(system, fql, potential)¶ The (local) DihedralHarmonic interaction using FixedQuadruple lists.