Fixednode diffusion Monte Carlo potential energy curve of the fluorine molecule F{sub 2} using selected configuration interaction trial wavefunctions
Abstract
The potential energy curve of the F{sub 2} molecule is calculated with FixedNode Diffusion Monte Carlo (FNDMC) using Configuration Interaction (CI)type trial wavefunctions. To keep the number of determinants reasonable and thus make FNDMC calculations feasible in practice, the CI expansion is restricted to those determinants that contribute the most to the total energy. The selection of the determinants is made using the CIPSI approach (Configuration Interaction using a Perturbative Selection made Iteratively). The trial wavefunction used in FNDMC is directly issued from the deterministic CI program; no Jastrow factor is used and no preliminary multiparameter stochastic optimization of the trial wavefunction is performed. The nodes of CIPSI wavefunctions are found to reduce significantly the fixednode error and to be systematically improved upon increasing the number of selected determinants. To reduce the nonparallelism error of the potential energy curve, a scheme based on the use of a Rdependent number of determinants is introduced. Using Dunning’s ccpVDZ basis set, the FNDMC energy curve of F{sub 2} is found to be of a quality similar to that obtained with full configuration interaction/ccpVQZ.
 Authors:
 Laboratoire de Chimie et Physique Quantiques, CNRSUniversité de Toulouse, Toulouse (France)
 Publication Date:
 OSTI Identifier:
 22416041
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CONFIGURATION INTERACTION; DIAGRAMS; DIFFUSION; EXPANSION; FLUORINE; ITERATIVE METHODS; MOLECULES; MONTE CARLO METHOD; OPTIMIZATION; POTENTIAL ENERGY; STOCHASTIC PROCESSES; WAVE FUNCTIONS
Citation Formats
Giner, Emmanuel, Scemama, Anthony, and Caffarel, Michel. Fixednode diffusion Monte Carlo potential energy curve of the fluorine molecule F{sub 2} using selected configuration interaction trial wavefunctions. United States: N. p., 2015.
Web. doi:10.1063/1.4905528.
Giner, Emmanuel, Scemama, Anthony, & Caffarel, Michel. Fixednode diffusion Monte Carlo potential energy curve of the fluorine molecule F{sub 2} using selected configuration interaction trial wavefunctions. United States. doi:10.1063/1.4905528.
Giner, Emmanuel, Scemama, Anthony, and Caffarel, Michel. 2015.
"Fixednode diffusion Monte Carlo potential energy curve of the fluorine molecule F{sub 2} using selected configuration interaction trial wavefunctions". United States.
doi:10.1063/1.4905528.
@article{osti_22416041,
title = {Fixednode diffusion Monte Carlo potential energy curve of the fluorine molecule F{sub 2} using selected configuration interaction trial wavefunctions},
author = {Giner, Emmanuel and Scemama, Anthony and Caffarel, Michel},
abstractNote = {The potential energy curve of the F{sub 2} molecule is calculated with FixedNode Diffusion Monte Carlo (FNDMC) using Configuration Interaction (CI)type trial wavefunctions. To keep the number of determinants reasonable and thus make FNDMC calculations feasible in practice, the CI expansion is restricted to those determinants that contribute the most to the total energy. The selection of the determinants is made using the CIPSI approach (Configuration Interaction using a Perturbative Selection made Iteratively). The trial wavefunction used in FNDMC is directly issued from the deterministic CI program; no Jastrow factor is used and no preliminary multiparameter stochastic optimization of the trial wavefunction is performed. The nodes of CIPSI wavefunctions are found to reduce significantly the fixednode error and to be systematically improved upon increasing the number of selected determinants. To reduce the nonparallelism error of the potential energy curve, a scheme based on the use of a Rdependent number of determinants is introduced. Using Dunning’s ccpVDZ basis set, the FNDMC energy curve of F{sub 2} is found to be of a quality similar to that obtained with full configuration interaction/ccpVQZ.},
doi = {10.1063/1.4905528},
journal = {Journal of Chemical Physics},
number = 4,
volume = 142,
place = {United States},
year = 2015,
month = 1
}

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