Free energies of molecular clusters determined by guided mechanical disassembly

Abstract

The excess free energy of a molecular cluster is a key quantity in models of the nucleation of droplets from a metastable vapour phase; it is often viewed as the free energy arising from the presence of an interface between the two phases. We show how this quantity can be extracted from simulations of the mechanical disassembly of a cluster using guide particles in molecular dynamics. We disassemble clusters ranging in size from 5 to 27 argon-like Lennard-Jones atoms, thermalised at 60 K, and obtain excess free energies, by means of the Jarzynski equality, that are consistent with previous studies. We only simulate the cluster of interest, in contrast to approaches that require a series of comparisons to be made between clusters differing in size by one molecule. We discuss the advantages and disadvantages of the scheme and how it might be applied to more complex systems.

References in corpus (10)

• A nonequilibrium equality for free energy differences
• Equilibrium free energy differences from nonequilibrium measurements: a master equation approach
• Verification of the Crooks fluctuation theorem and recovery of RNA folding free energies
• A "fast growth" method of computing free energy differences
• A two-state kinetic model for the unfolding of single molecules by mechanical force
• On practical applicability of the Jarzynski relation in statistical mechanics: a pedagogical example
• Computing absolute free energies of disordered structures by molecular simulation
• Estimate of the free energy difference in mechanical systems from work fluctuations: experiments and models
• Work distribution functions in polymer stretching experiments
• Experimental study of work fluctuations in a harmonic oscillator

Cited by in corpus (2)

• A classical reactive potential for molecular clusters of sulphuric acid and water
• Free energy of formation of clusters of sulphuric acid and water molecules determined by guided disassembly