espressopp.interaction.CoulombKSpaceP3M

Coulomb potential and interaction Objects (K space part)

This is the K space part of potential of Coulomb long range interaction according to the P3M summation technique. Good explanation of P3M summation could be found here [Allen89], [Deserno98].

Example:

>>> ewaldK_pot = espressopp.interaction.CoulombKSpaceP3M(system, coulomb_prefactor, alpha, kspacecutoff)
>>> ewaldK_int = espressopp.interaction.CellListCoulombKSpaceP3M(system.storage, ewaldK_pot)
>>> system.addInteraction(ewaldK_int)

!IMPORTANT Coulomb interaction needs R space part as well CoulombRSpace.

Definition:

It provides potential object CoulombKSpaceP3M and interaction object CellListCoulombKSpaceP3M based on all particles list.

The potential is based on the system information (System) and parameters: Coulomb prefactor (coulomb_prefactor), P3M parameter (alpha), and the cutoff in K space (kspacecutoff).

>>> ewaldK_pot = espressopp.interaction.CoulombKSpaceP3M(system, coulomb_prefactor, alpha, kspacecutoff)

Potential Properties:

  • ewaldK_pot.prefactor

    The property ‘prefactor’ defines the Coulomb prefactor.

  • ewaldK_pot.alpha

    The property ‘alpha’ defines the P3M parameter \(\\alpha\).

  • ewaldK_pot.kmax

    The property ‘kmax’ defines the cutoff in K space.

The interaction is based on the all particles list. It needs the information from Storage and K space part of potential.

>>> ewaldK_int = espressopp.interaction.CellListCoulombKSpaceP3M(system.storage, ewaldK_pot)

Interaction Methods:

  • getPotential()

    Access to the local potential.

Adding the interaction to the system:

>>> system.addInteraction(ewaldK_int)
espressopp.interaction.CoulombKSpaceP3M(system, C_pref, alpha, M, P, rcut, interpolation)
Parameters:
  • system –
  • C_pref –
  • alpha –
  • M –
  • P –
  • rcut –
  • interpolation (int) – (default: 200192)
espressopp.interaction.CellListCoulombKSpaceP3M(storage, potential)
Parameters:
  • storage –
  • potential –
espressopp.interaction.CellListCoulombKSpaceP3M.getPotential()
Return type: