title: Accurate Ab initio calculation of ionization potentials of the first-row transition metals with the configuration-interaction quantum Monte Carlo technique.
abstract: Accurate ionization potentials of the first-row transition-metal atoms are obtained via the initiator full configuration quantum Monte Carlo technique, performing a stochastic integration of the electronic Schrödinger equation in exponentially large Hilbert spaces, with a mean absolute error of 0.13  kcal/mol (5 meV). This accuracy requires correlation of the 3p semicore electrons and in some cases the 3s manifold, along with extrapolation of the correlation energies to the complete-basis-set limit, and provides a new theoretical benchmark for the ionization potentials of these systems.
authors: The University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors: Robert E
authors: RE
authors: Thomas
authors: The University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom and Theory and Simulation of Condensed Matter, King's College London, Strand, London WC2 R 2LS, United Kingdom.
authors: George H
authors: GH
authors: Booth
authors: The University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom and Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.
authors: Ali
authors: A
authors: Alavi