Stochastic boundary conditions for grand-canonical-like molecular dynamics simulations of open systems

In this paper we develop a stochastic boundary conditions (SBC) for event-driven molecular dynamics simulations of a finite volume embedded within an infinite environment. In this method, we first collect the statistics of injection/ejection events in periodic boundary conditions (PBC). Once suffici...

Full description

Bibliographic Details
Main Authors: Prusty, Manamohan, Leaw, Jianing, Chong, Shan Shang, Cheong, Siew Ann
Other Authors: School of Physical and Mathematical Sciences
Format: Journal Article
Language:English
Published: 2013
Online Access:https://hdl.handle.net/10356/97011
http://hdl.handle.net/10220/13139
Description
Summary:In this paper we develop a stochastic boundary conditions (SBC) for event-driven molecular dynamics simulations of a finite volume embedded within an infinite environment. In this method, we first collect the statistics of injection/ejection events in periodic boundary conditions (PBC). Once sufficient statistics are collected, we remove the PBC and turn on the SBC. In the SBC simulations, we allow particles leaving the system to be truly ejected from the simulation, and randomly inject particles at the boundaries by resampling from the injection/ejection statistics collected from the current or previous simulations. With the SBC, we can measure thermodynamic quantities within the grand canonical ensemble, based on the particle number and energy fluctuations. To demonstrate how useful the SBC algorithm is, we simulated a hard disk gas and measured the pair distribution function, the compressibility and the specific heat, comparing them against literature values.