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

espressopp.interaction.DihedralHarmonic(K, phi0)
Parameters:

  • K (real) – (default: 0.0)

  • phi0 (real) – (default: 0.0)

espressopp.interaction.FixedQuadrupleListDihedralHarmonic(system, fql, potential)
Parameters:

  • system

  • fql

  • potential

espressopp.interaction.FixedQuadrupleListDihedralHarmonic.getFixedQuadrupleList()
Return type:

A Python list of lists.

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)
class espressopp.interaction.DihedralHarmonic.DihedralHarmonic(*args, **kwds)

The DihedralHarmonic potential.

class espressopp.interaction.DihedralHarmonic.FixedQuadrupleListDihedralHarmonicLocal(system, fql, potential)

The (local) DihedralHarmonic interaction using FixedQuadruple lists.

getFixedQuadrupleList((interaction_FixedQuadrupleListDihedralHarmonic)arg1) → FixedQuadrupleList :
C++ signature :

std::shared_ptr<espressopp::FixedQuadrupleList> getFixedQuadrupleList(espressopp::interaction::FixedQuadrupleListInteractionTemplate<espressopp::interaction::DihedralHarmonic> {lvalue})

setPotential((interaction_FixedQuadrupleListDihedralHarmonic)arg1, (interaction_DihedralHarmonic)arg2) → None :
C++ signature :

void setPotential(espressopp::interaction::FixedQuadrupleListInteractionTemplate<espressopp::interaction::DihedralHarmonic> {lvalue},std::shared_ptr<espressopp::interaction::DihedralHarmonic>)