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

A. Scemama, T. Applencourt, E. Giner, M. Caffarel
2014 Journal of Chemical Physics  
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
more » ... de 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, $|E_c|$.
doi:10.1063/1.4903985 pmid:25554136 fatcat:2ufp6zag5va45gpqdordfmla7a