Quasi-boundary based on exchange symmetry theory for multilevel simulations

Abstract

In this contribution we propose a novel method (QUEST) which enables the simulation of diffusive systems through quantum mechanical/molecular mechanical (QM/MM) molecular dynamics. The method is an evolution of boundary based on exchange symmetry theory (BEST), an approach based on imposing a bias potential to hinder exchanges between QM and MM particles. This new method corrects for the main shortcoming of BEST, namely that only static properties could be studied, as the dynamics was disrupted. With Quasi-BEST (QUEST) the dynamics is still preserved, albeit at some additional cost in the computation of energy and forces as they are needed for the exchanged configurations between QM and MM particles. Here we describe the theoretical basis of QUEST, and we present the results on a small toy system.

Keywords::

• QM/MM
• molecular dynamics
• exchange symmetry

Notes

^1. Present Address: Institut für Physikalische und Theoretische Chemie, Goethe Universität Frankfurt Max–von–Laue–Str. 7, D–60438 Frankfurt am Main, Germany.

Additional information

Funding

The authors thank the Visiting Professor Programme of ‘Regione Autonoma della Sardegna’ (L.R. 3/2008) for supporting the travel of M.S. A part of this research was supported by Grants-in-Aid for Scientific Research, MEXT.