DL_MULTI - A molecular dynamics program to use distributed multipole electrostatic models to simulate the dynamics of organic crystals

Maurice Leslie (1)

1 STFC Daresbury Laboratory

DL_MULTI has been developed to extend the Molecular Dynamics simulation program DL_POLY [1] to model rigid molecules whose intermolecular interactions include a distributed multipole model for the electrostatic interactions. The adaptations use anisotropic atom-atom potentials, corresponding to atomic multipoles up to hexadecapole. The lattice sums of these multipoles are evaluated using the Ewald method, using a technique using Stone's S functions [2] which describes the multipoles in a molecule fixed reference frame. An algorithm for determining suitable cutoffs is described and errors in the direct space part of the Ewald summation discussed. Thus DL MULTI provides a general purpose MD program for studying polar rigid organic molecules in their liquid and crystalline states with a realistic intermolecular potential suitable for studying polymorphism. Example applications to uracil and 5-azauracil show that, with the new summation method, a realistic electrostatic model can be used without excessive computer time being used.

Mots clés: Physical Sciences

Maurice Leslie. DL_MULTI - A molecular dynamics program to use distributed multipole electrostatic models to simulate the dynamics of organic crystals. Molecular Physics, 2008, 106 (12-13), pp.1567-1578. ⟨10.1080/00268970802175308⟩. ⟨hal-00513210⟩