title: Communication: energy benchmarking with quantum Monte Carlo for water nano-droplets and bulk liquid water.
abstract: We show the feasibility of using quantum Monte Carlo (QMC) to compute benchmark energies for configuration samples of thermal-equilibrium water clusters and the bulk liquid containing up to 64 molecules. Evidence that the accuracy of these benchmarks approaches that of basis-set converged coupled-cluster calculations is noted. We illustrate the usefulness of the benchmarks by using them to analyze the errors of the popular BLYP approximation of density functional theory (DFT). The results indicate the possibility of using QMC as a routine tool for analyzing DFT errors for non-covalent bonding in many types of condensed-phase molecular system.
authors.affiliation: Department of Earth Sciences, University College London, London WC1E 6BT, United Kingdom.
authors.forename: D
authors.initials: D
authors.lastname: Alfè
authors.forename: A P
authors.initials: AP
authors.lastname: Bartók
authors.forename: G
authors.initials: G
authors.lastname: Csányi
authors.forename: M J
authors.initials: MJ
authors.lastname: Gillan