Quantum Free Energies: Isotope Fractionation

This lecture covers advanced techniques for computing quantum free energies, focusing on isotope fractionation. It discusses the scaling of masses to compute overall free-energy differences, with applications in geochemistry and atmospheric sciences. Various estimators and methods are explored, including scaled-coordinates estimators and fourth-order versions. The lecture also addresses the challenges of sampling the isobaric ensemble and the use of path integral replica exchange for efficient sampling.