Path integral computation of quantum free energy differences due to alchemical transformations involving mass and potential

Alejandro Pérez, O. Anatole Von Lilienfeld

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)

Abstract

Thermodynamic integration, perturbation theory, and λ-dynamics methods were applied to path integral molecular dynamics calculations to investigate free energy differences due to "alchemical" transformations. Several estimators were formulated to compute free energy differences in solvable model systems undergoing changes in mass and/or potential. Linear and nonlinear alchemical interpolations were used for the thermodynamic integration. We find improved convergence for the virial estimators, as well as for the thermodynamic integration over nonlinear interpolation paths. Numerical results for the perturbative treatment of changes in mass and electric field strength in model systems are presented. We used thermodynamic integration in ab initio path integral molecular dynamics to compute the quantum free energy difference of the isotope transformation in the Zundel cation. The performance of different free energy methods is discussed.

Original languageEnglish
Pages (from-to)2358-2369
Number of pages12
JournalJournal of Chemical Theory and Computation
Volume7
Issue number8
DOIs
Publication statusPublished - Aug 9 2011
Externally publishedYes

ASJC Scopus subject areas

  • Computer Science Applications
  • Physical and Theoretical Chemistry

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