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Title: Auxiliary-field quantum Monte Carlo calculations of the molybdenum dimer

Chemical accuracy is difficult to achieve for systems with transition metal atoms. Third row transition metal atoms are particularly challenging due to strong electron-electron correlation in localized d-orbitals. The Cr 2 molecule is an outstanding example, which we previously treated with highly accurate auxiliary-field quantum Monte Carlo (AFQMC) calculations. Somewhat surprisingly, computational description of the isoelectronic Mo 2 dimer has also, to date, been scattered and less than satisfactory. We present high-level theoretical benchmarks of the Mo 2 singlet ground state (X 1Σ + g) and first triplet excited state (a 3Σ + u), using the phaseless AFQMC calculations. Extrapolation to the complete basis set limit is performed. Furthermore, excellent agreement with experimental spectroscopic constants is obtained. We also present a comparison of the correlation effects in Cr 2 and Mo 2.
Authors:
ORCiD logo [1] ;  [2] ;  [2]
  1. College of William and Mary, Williamsburg, VA (United States); Old Dominion Univ., Norfolk, VA (United States)
  2. College of William and Mary, Williamsburg, VA (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; FG02-09ER16046; FG02-11ER16257
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 144; Journal Issue: 24; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
UT-Battelle LLC, Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1467572
Alternate Identifier(s):
OSTI ID: 1259372

Purwanto, Wirawan, Zhang, Shiwei, and Krakauer, Henry. Auxiliary-field quantum Monte Carlo calculations of the molybdenum dimer. United States: N. p., Web. doi:10.1063/1.4954245.
Purwanto, Wirawan, Zhang, Shiwei, & Krakauer, Henry. Auxiliary-field quantum Monte Carlo calculations of the molybdenum dimer. United States. doi:10.1063/1.4954245.
Purwanto, Wirawan, Zhang, Shiwei, and Krakauer, Henry. 2016. "Auxiliary-field quantum Monte Carlo calculations of the molybdenum dimer". United States. doi:10.1063/1.4954245. https://www.osti.gov/servlets/purl/1467572.
@article{osti_1467572,
title = {Auxiliary-field quantum Monte Carlo calculations of the molybdenum dimer},
author = {Purwanto, Wirawan and Zhang, Shiwei and Krakauer, Henry},
abstractNote = {Chemical accuracy is difficult to achieve for systems with transition metal atoms. Third row transition metal atoms are particularly challenging due to strong electron-electron correlation in localized d-orbitals. The Cr2 molecule is an outstanding example, which we previously treated with highly accurate auxiliary-field quantum Monte Carlo (AFQMC) calculations. Somewhat surprisingly, computational description of the isoelectronic Mo2 dimer has also, to date, been scattered and less than satisfactory. We present high-level theoretical benchmarks of the Mo2 singlet ground state (X1Σ+g) and first triplet excited state (a3Σ+u), using the phaseless AFQMC calculations. Extrapolation to the complete basis set limit is performed. Furthermore, excellent agreement with experimental spectroscopic constants is obtained. We also present a comparison of the correlation effects in Cr2 and Mo2.},
doi = {10.1063/1.4954245},
journal = {Journal of Chemical Physics},
number = 24,
volume = 144,
place = {United States},
year = {2016},
month = {6}
}