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arXiv · 1107.3330

A fast Variational Gaussian Wave-packet method: Size-induced structural transitions in large neon clusters

Ionuţ Georgescu·Vladimir A. Mandelshtam
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Abstract

The Variational Gaussian wavepacket (VGW) method is an alternative to Path Integral Monte-Carlo (PIMC) for the computation of thermodynamic properties of many-body systems at thermal equilibrium. It provides a direct access to the thermal density matrix and is particularly efficient for Monte-Carlo approaches, as for an N-body system it operates in a non-inflated 3N dimensional configuration space. Here we greatly accelerate the VGW method by retaining only the relevant short-range correlations in the (otherwise full) $3N\times 3N$ Gaussian width matrix without sacrificing the accuracy of the fully-coupled VGW method. This results in the reduction of the original $\mathcal{O}(N^3)$ scaling to $\mathcal{O}(N^2)$. The Fast-VGW method is then applied to quantum Lennard-Jones clusters with sizes up to N=6500 atoms. Following Doye and Calvo [JCP 116, 8307 (2002)] we study the competition between the icosahedral and decahedral structural motifs in Ne_N clusters as a function of N.

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BibTeXRIS

Ionuţ Georgescu, Vladimir A. Mandelshtam. 2011-07-20. A fast Variational Gaussian Wave-packet method: Size-induced structural transitions in large neon clusters. https://doi.org/10.1063/1.3651473

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