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arXiv · 1409.3671

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

A. Scemama·T. Applencourt·E. Giner·M. Caffarel
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Abstract

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 method (Configuration Interaction using a Perturbative Selection made Iteratively) and including the most prominent determinants of the full CI 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. The FN-DMC/(CIPSI nodes) ground-state energies presented here are, to the best of our knowledge, the most accurate values reported so far. Thanks to the variational property of FN-DMC total energies, the results also provide lower bounds for the absolute value of all-electron correlation energies, $|E_c|$.

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A. Scemama, T. Applencourt, E. Giner, M. Caffarel. 2014-09-12. Accurate nonrelativistic ground-state energies of 3d transition metal atoms. https://doi.org/10.1063/1.4903985

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