Summary: A simple method for sampling partition function ratios
Andreas Schu®ring a
, Scott M. Auerbach b
, Siegfried Fritzsche a,*
University of Leipzig, Faculty of Physics and Geosciences, Institute of Theoretical Physics, Postfach 100920, 04009 Leipzig, Germany
Department of Chemistry and Department of Chemical Engineering, University of Massachusettes, Amherst, MA 01003, USA
Received 25 July 2007; in final form 2 November 2007
Available online 7 November 2007
A simple simulation method is proposed for calculating partition function ratios with emphasis on computing transition state theory
rate constants. Potential energy histograms are calculated in one single high temperature simulation. Partition function ratios can then be
computed for a wide range of temperatures from this information. We apply this high-temperature configuration-space exploration
(HTCE) method to a model problem. We find that HTCE quantitatively reproduces rate constants evaluated using brute-force molecular
dynamics, and using Voter's displacement vector method. HTCE is extremely straightforward to implement and it offers other system
information that targeted free-energy simulations may not.
” 2007 Elsevier B.V. All rights reserved.
Transition state theory (TST) provides the conceptual