Locality Error Free Effective Core Potentials of 3d Transition Metal Elements for the Diffusion Monte Carlo method*

Locality errors have limited the scope and accuracy of the application of diffusion Monte Carlo (DMC) to materials. Transition metal oxide energies are particularly sensitive to locality errors in the pseudopotentials. Therefore, we developed locality error free effective core pseudo-Hamiltonians (PH) for 3d transition metals based on the framework described in M.C. Bennett et al, JCTC 18, 2 (2022). We carefully optimized our PHs and achieved accuracies similar to other state-of-the-art semilocal pseudopotentials used for DMC. In this talk, we will explain how our PHs differ from the conventional semilocal pseudopotentials and how we can avoid locality errors. We will discuss the transferability of our PHs as compared to state-of-the-art semilocal pseudopotentials and all-electron calculations with CCSD(T), coupled cluster singles, doubles, and perturbative triples.