Accurate nonrelativistic ground-state energies of 3d transition metal atoms

Journal Article · Sun Dec 28 04:00:00 EST 2014 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4903985· OSTI ID:22415407

Scemama, A.; Applencourt, T.; Giner, E.; Caffarel, M. ^[1]

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1. Lab. Chimie et Physique Quantiques, CNRS-Université de Toulouse, Toulouse (France)

We present accurate nonrelativistic ground-state energies of the transition metal atoms of the 3d series calculated with Fixed-Node Diffusion Monte Carlo (FN-DMC). Selected multi-determinantal expansions obtained with the CIPSI (Configuration Interaction using a Perturbative Selection made Iteratively) method and including the most prominent determinants of the full configuration interaction expansion are used as trial wavefunctions. Using a maximum of a few tens of thousands determinants, fixed-node errors on total DMC energies are found to be greatly reduced for some atoms with respect to those obtained with Hartree-Fock nodes. To the best of our knowledge, the FN-DMC/(CIPSI nodes) ground-state energies presented here are the lowest variational total energies reported so far. They differ from the recently recommended non-variational values of McCarthy and Thakkar [J. Chem. Phys. 136, 054107 (2012)] only by a few percents of the correlation energy. Thanks to the variational property of FN-DMC total energies, our results provide exact lower bounds for the absolute value of all-electron correlation energies, |E{sub c}|.

• OSTI ID: 22415407
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 24 Vol. 141; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOMS
CONFIGURATION INTERACTION
DIFFUSION
ELECTRON CORRELATION
GROUND STATES
HARTREE-FOCK METHOD
ITERATIVE METHODS
MONTE CARLO METHOD
TRANSITION ELEMENTS
VARIATIONAL METHODS