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Title: Calculating potential energy curves with fixed-node diffusion Monte Carlo: CO and N 2

Abstract

This study reports on the prospect for the routine use of Quantum Monte Carlo (QMC) for the electronic structure problem, applying fixed-node Diffusion Monte Carlo (DMC) to generate highly accurate Born-Oppenheimer potential energy curves (PECs) for small molecular systems. The singlet ground electronic states of CO and N 2 were used as test cases. The PECs obtained by DMC employing multiconfigurational trial wavefunctions were compared with those obtained by conventional high-accuracy electronic structure methods such as multireference configuration interaction and/or the best available empirical spectroscopic curves. The goal was to test whether a straightforward procedure using available QMC codes could be applied robustly and reliably. Results obtained with DMC codes were found to be in close agreement with the benchmark PECs, and the n 3 scaling with the number of electrons (compared with n 7 or worse for conventional high-accuracy quantum chemistry) could be advantageous depending on the system size. Due to a large pre-factor in the scaling, for the small systems tested here, it is currently still much more computationally intensive to compute PECs with QMC. Nevertheless, QMC algorithms are particularly well-suited to large-scale parallelization and are therefore likely to become more relevant for future massively parallel hardware architectures.

Authors:
 [1];  [1]
  1. Missouri Univ. of Science and Technology, Rolla, MO (United States). Dept. of Chemistry
Publication Date:
Research Org.:
Missouri Univ. of Science and Technology, Rolla, MO (United States). Dept. of Chemistry
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1465366
Alternate Identifier(s):
OSTI ID: 1335711
Grant/Contract Number:  
SC0010616
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 145; Journal Issue: 22; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Powell, Andrew D., and Dawes, Richard. Calculating potential energy curves with fixed-node diffusion Monte Carlo: CO and N2. United States: N. p., 2016. Web. doi:10.1063/1.4971378.
Powell, Andrew D., & Dawes, Richard. Calculating potential energy curves with fixed-node diffusion Monte Carlo: CO and N2. United States. doi:10.1063/1.4971378.
Powell, Andrew D., and Dawes, Richard. Wed . "Calculating potential energy curves with fixed-node diffusion Monte Carlo: CO and N2". United States. doi:10.1063/1.4971378. https://www.osti.gov/servlets/purl/1465366.
@article{osti_1465366,
title = {Calculating potential energy curves with fixed-node diffusion Monte Carlo: CO and N2},
author = {Powell, Andrew D. and Dawes, Richard},
abstractNote = {This study reports on the prospect for the routine use of Quantum Monte Carlo (QMC) for the electronic structure problem, applying fixed-node Diffusion Monte Carlo (DMC) to generate highly accurate Born-Oppenheimer potential energy curves (PECs) for small molecular systems. The singlet ground electronic states of CO and N2 were used as test cases. The PECs obtained by DMC employing multiconfigurational trial wavefunctions were compared with those obtained by conventional high-accuracy electronic structure methods such as multireference configuration interaction and/or the best available empirical spectroscopic curves. The goal was to test whether a straightforward procedure using available QMC codes could be applied robustly and reliably. Results obtained with DMC codes were found to be in close agreement with the benchmark PECs, and the n3 scaling with the number of electrons (compared with n7 or worse for conventional high-accuracy quantum chemistry) could be advantageous depending on the system size. Due to a large pre-factor in the scaling, for the small systems tested here, it is currently still much more computationally intensive to compute PECs with QMC. Nevertheless, QMC algorithms are particularly well-suited to large-scale parallelization and are therefore likely to become more relevant for future massively parallel hardware architectures.},
doi = {10.1063/1.4971378},
journal = {Journal of Chemical Physics},
number = 22,
volume = 145,
place = {United States},
year = {Wed Dec 14 00:00:00 EST 2016},
month = {Wed Dec 14 00:00:00 EST 2016}
}

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Works referenced in this record:

General atomic and molecular electronic structure system
journal, November 1993

  • Schmidt, Michael W.; Baldridge, Kim K.; Boatz, Jerry A.
  • Journal of Computational Chemistry, Vol. 14, Issue 11, p. 1347-1363
  • DOI: 10.1002/jcc.540141112