 
Summary: Stochastic molecular dynamics: A combined Monte Carlo and molecular
dynamics technique for isothermal simulations
Phil Attard
Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 Australia
Received 24 January 2002; accepted 21 March 2002
A hybrid Monte Carlo molecular dynamics technique is developed that gives equations of motion
for an isothermal system. Test results for a LennardJones fluid are shown to be in good agreement
with the known equation of state. The physical interpretation of the procedure and the extension to
isothermalisobaric systems is also discussed. © 2002 American Institute of Physics.
DOI: 10.1063/1.1478057
I. INTRODUCTION
Each of the two main simulation techniquesMonte
Carlo and molecular dynamicshas their own advantage.
The molecular dynamics method can be used for time
dependent phenomena because it solves the equations of mo
tion along a trajectory. In contrast the Monte Carlo method
generates a sequence of states that yields the desired prob
ability distribution, and while this precludes the study of dy
namics, it does allow the trajectory to be optimized to cover
the important states of the system in an efficient manner. In
