Applications of DL_POLY and DL_MULTI to organic molecular crystals

Sarah Lois Price (1) , Said Hamad (2) , Antonio Torrisi (2) , Panagiotis Karamertzanis (1) , Maurice Leslie (3) , Richard Catlow (1, 4, 5)

1 Chemistry
2 Royal Insitution of Great Britain
3 CCLRC Daresbury Laboratory
4 Royal Institution of Great Britain
5 Royal Institution of Great Britain

Molecular Dynamics simulations are capable of giving considerable insight into the polymorphism of organic molecules, a problem of major concern to the pharmaceutical and other speciality chemicals industries. We illustrate some of the challenges involved in small organic systems which have complex solid state phase behaviour, including characterising rotationally disordered phases, modelling polymorphs with very different hydrogen bonding motifs and explaining the solvent dependence of a polymorphic system. Simulating the dynamics within the organic solid state can be very demanding of the model for the weak forces between the molecules. This has led to the development of DL_MULTI so that a distributed multipole electrostatic model can be used to describe the orientation dependence of hydrogen bonding and π-π stacking more realistically. Once a simulation is correctly reproducing the known crystal structures, there are also considerable system-specific challenges in extracting novel insights from the MD simulations.

Mots clés: Physical Sciences

Sarah Lois Price, Said Hamad, Antonio Torrisi, Panagiotis Karamertzanis, Maurice Leslie, et al.. Applications of DL_POLY and DL_MULTI to organic molecular crystals. Molecular Simulation, 2007, 32 (12-13), pp.985-997. ⟨10.1080/08927020600880810⟩. ⟨hal-00514994⟩