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Reconstructing the Density of States by History-Dependent Metadynamics

2004; American Physical Society; Volume: 92; Issue: 17 Linguagem: Inglês

10.1103/physrevlett.92.170601

1092-0145

Cristian Micheletti, Alessandro Laio, Michele Parrinello,

Statistical Mechanics and Entropy

We present a novel method for the calculation of the energy density of states $D(E)$ for systems described by classical statistical mechanics. The method builds on an extension of a recently proposed strategy that allows the free-energy profile of a canonical system to be recovered within a preassigned accuracy [A. Laio and M. Parrinello, Proc. Natl. Acad. Sci. U.S.A. 99, 12562 (2002)]. The method allows a good control over the error on the recovered system entropy. This fact is exploited to obtain $D(E)$ more efficiently by combining measurements at different temperatures. The accuracy and efficiency of the method are tested for the two-dimensional Ising model (up to size $50\ifmmode\times\else\texttimes\fi{}50$) by comparison with both exact results and previous studies. This method is a general one and should be applicable to more realistic model systems.