Intermediate Thermodynamic States Contribute Equally to Free Energy Convergence: A Demonstration with Replica Exchange

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• 作者：Trung Hai Nguyen ; David D. L. Minh
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2016
• 出版时间：May 10, 2016
• 年：2016
• 卷：12
• 期：5
• 页码：2154-2161
• 全文大小：501K
• 年卷期：0
• ISSN：1549-9626

文摘

We investigate the relationship between the number of intermediate thermodynamic states along a pathway and the precision of free energy estimates. With a sufficient number of states, the asymptotic variance collapses as a function of the total sample size. Our analytical result is corroborated by replica exchange molecular dynamics simulations of model systems in which the neighbor exchange rate exceeds 35%. Precision collapse is also observed in heat capacity estimates based on the multistate Bennett acceptance ratio. In contrast to the relaxation and mean first-passage times, the autocorrelation time of state indices is found to be relevant to free energy convergence.