Using DL_POLY to study the sensitivity of liquid structure to potential parameters

Abstract

Two case studies are presented showing the local structure in liquids and how it responds to changes in the intermolecular potential. The idea is to use realistic and unrealistic potentials in order to determine the sensitivity of local liquid structure to potential parameters. The first case study concerns two families of modified water models. In the “hybrid” family, the hydrogen bond strength is reduced, but the geometry kept constant; in the second family, the molecular geometry is changed by reducing the bond angle, keeping a constant molecular dipole moment. The local structure is measured by radial distribution functions, three-dimensional probability distribution functions and three-body angular correlations. The second case study concerns the ionic liquid dimethylimidazolium chloride ([C₁mim]Cl). The effect of reducing the hydrogen bonding potential of the cations while maintaining their charge is examined.

Keywords:

• Molecular dynamics
• Hydrogen bonding
• Force fields
• Liquid structure

Acknowledgements

We thank J. Kohanoff, M. Del Pópolo and T. Head-Gordon for discussions and EPSRC (grants GR/S41562 and EP/D029538/1) and the Leverhulme Trust (Emeritus Fellowship to RMLB) for financial support.

Notes

^¶ [email protected].

Additional information

Notes on contributors

T. G. A. Youngs

¶ ¶ [email protected].