title: Path Integral Computation of Quantum Free Energy Differences Due to Alchemical Transformations Involving Mass and Potential.
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.
authors.affiliation: Department of Chemistry, New York University , New York, New York 10003, United States, Nano-bio spectroscopy group, Centro Joxe Mari Korta , Avenida de Tolosa, 72, E-20018 Donostia-San Sebastian, Spain, and Institute of Pure and Applied Mathematics, University of California Los Angeles , Los Angeles, California 90095, United States.|Surface and Interface Sciences Department, Sandia National Laboratories , Albuquerque, New Mexico 87185, United States, Argonne Leadership Computing Facility, Argonne National Laboratory , Argonne, Illinois 60439, United States, and Institute of Pure and Applied Mathematics, University of California Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Pérez
authors.affiliation: Department of Chemistry, New York University , New York, New York 10003, United States, Nano-bio spectroscopy group, Centro Joxe Mari Korta , Avenida de Tolosa, 72, E-20018 Donostia-San Sebastian, Spain, and Institute of Pure and Applied Mathematics, University of California Los Angeles , Los Angeles, California 90095, United States.|Surface and Interface Sciences Department, Sandia National Laboratories , Albuquerque, New Mexico 87185, United States, Argonne Leadership Computing Facility, Argonne National Laboratory , Argonne, Illinois 60439, United States, and Institute of Pure and Applied Mathematics, University of California Los Angeles , Los Angeles, California 90095, United States.
authors.forename: O Anatole
authors.initials: OA
authors.lastname: von Lilienfeld