2016/04/07 by Michel Caffarel, Thomas Applencourt, Emmanuel Giner +1 · 3 citations
Chemical Engineering · Materials Science · Mathematics · Physics and Astronomy · #Advanced Chemical Physics Studies #Basis (linear algebra) #Basis set #Catalysis and Oxidation Reactions #Catalytic Processes in Materials Science #Configuration interaction #Diffusion Monte Carlo #Dynamic Monte Carlo method #Energy (signal processing) #Full configuration interaction #Function (biology) #Geometry #Ground state #Markov chain Monte Carlo #Mathematical analysis #Mathematics #Molecule #Monte Carlo method #Monte Carlo molecular modeling #Node (physics) #Physics #Quantum Monte Carlo #Quantum mechanics #Statistical physics #Statistics #Upper and lower bounds #Wave function #physics.chem-ph
paper · pdf · doi:10.1063/1.4947093
5 pages, 1 figure
arxiv created 2016/04/07 · openalex publication_date 2016/04/20 · arxiv updated 2016/05/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
All-electron Fixed-node DiffusionMonte Carlo calculations for the nonrelativistic ground-state energy of the water molecule at equilibrium geometry are presented. The determinantal part of the trial wavefunction is obtained from a selected Configuration Interaction calculation[Configuration Interaction using a Perturbative Selection done Iteratively (CIPSI) method] including up to about 1.4 × 10(6) of determinants. Calculations are made using the cc-pCVnZ family of basis sets, with n = 2 to 5. In contrast with most quantum Monte Carlo works no re-optimization of the determinantal part in presence of a Jastrow is performed. For the largest cc-pCV5Z basis set the lowest upper bound for the ground-state energy reported so far of -76.437 44(18) is obtained. The fixed-node energy is found to decrease regularly as a function of the cardinal numbern and the Complete Basis Set limit associated with exact nodes is easily extracted. The resulting energy of -76.438 94(12) - in perfect agreement with the best experimentally derived value - is the most accurate theoretical estimate reported so far. We emphasize that employing selected configuration interactionnodes of increasing quality in a given family of basis sets may represent a simple, deterministic, reproducible, and systematic way of controlling the fixed-node error in diffusionMonte Carlo.