skip to main content

SciTech ConnectSciTech Connect

Title: Unbiased free energy estimates in fast nonequilibrium transformations using Gaussian mixtures

In this paper, we present an improved method for obtaining unbiased estimates of the free energy difference between two thermodynamic states using the work distribution measured in nonequilibrium driven experiments connecting these states. The method is based on the assumption that any observed work distribution is given by a mixture of Gaussian distributions, whose normal components are identical in either direction of the nonequilibrium process, with weights regulated by the Crooks theorem. Using the prototypical example for the driven unfolding/folding of deca-alanine, we show that the predicted behavior of the forward and reverse work distributions, assuming a combination of only two Gaussian components with Crooks derived weights, explains surprisingly well the striking asymmetry in the observed distributions at fast pulling speeds. The proposed methodology opens the way for a perfectly parallel implementation of Jarzynski-based free energy calculations in complex systems.
Authors:
 [1]
  1. Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy and Centro Interdipartimentale per lo Studio delle Dinamiche Complesse (CSDC), Via Sansone 1, I-50019 Sesto Fiorentino (Italy)
Publication Date:
OSTI Identifier:
22415666
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 15; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALANINES; ASYMMETRY; FREE ENERGY; GAUSS FUNCTION; MIXTURES; THERMODYNAMICS; TRANSFORMATIONS; VELOCITY