Phase changes in 38-atom Lennard-Jones clusters. I. A parallel tempering study in the canonical ensemble

Abstract

The heat capacity and isomer distributions of the 38-atom Lennard-Jones cluster have been calculated in the canonical ensemble using parallel tempering Monte Carlo methods. A distinct region of temperature is identified that corresponds to equilibrium between the global minimum structure and the icosahedral basin of structures. This region of temperatures occurs below the melting peak of the heat capacity and is accompanied by a peak in the derivative of the heat capacity with temperature. Parallel tempering is shown to introduce correlations between results at different temperatures. A discussion is given that compares parallel tempering with other related approaches that ensure ergodic simulations.

Structural Transitions and Melting in LJ74-78 Lennard-Jones Clusters from Adaptive Exchange Monte Carlo Simulations

“…10,11,[17][18][19] Depending on the structure of the global minimum, a LJ cluster may undergo one or more structural transformations according to the following general rules. Below size 31, the ground-state geometry is based on the polyicosahedral or antiMackay motif.…”

A Drude-model approach to dispersion interactions in dipole-bound anions

“…The acceptance criterion used for these moves assures detailed balance is obeyed. 151 In this study, simulations of (H 2 O) 6 and (H 2 O) 6 -were carried out at eight temperatures, in a geometric ratio 154 In simulating the anionic water clusters, there is the distinct possibility of sampling configurations for which the "anion" lies energetically above the neutral cluster (at the same geometry). Such configurations would be subject to electron autoionization, giving the neutral cluster plus a free electron.…”

“…The Monte-Carlo simulations were carried out using the parallel tempering algorithm 151 to avoid quasi-ergodic behavior caused by large energy barriers. With this algorithm, simulations for a series of replicas (each at a different temperature) are carried out in parallel, with most attempted moves being confined to individual replicas and carried out using the Metropolis algorithm.…”

Statistical Analysis of Ion Mobility Spectrometry. I. Unbiased and Guided Replica-Exchange Molecular Dynamics

“…The idea is then that high temperature replicas will explore broader regions of the energy landscape, and the exchange process can communicate the various basins of attraction to lower temperature replicas. The method is particularly suitable for multiple funnel landscapes [18], however, it becomes less efficient in systems with numerous degrees of freedom because the probability of a successful exchange drastically drops unless a larger number of replicas are used.…”