Density functional embedding for periodic and nonperiodic diffusion Monte Carlo calculations

Abstract

We present density functional embedding for diffusion Monte Carlo calculations (DMC). Using two test systems, an H chain and a Be slab, we demonstrate the feasibility and show that the approach can give high-quality results. DMC embedded in potentials from density functional embedding theory thus presents an alternative to conventional embedded quantum chemical methods, such as embedded complete active space calculations. This is especially true for cases in which the cluster size becomes too large for accurate wave-function theory based methods or for cases in which basis-set superposition errors become dominant. Furthermore, we show that embedded DMC can easily be used for systems in which the cluster of interest is a one-dimensional or two-dimensional periodic object and cannot be described as isolated impurity. This extends the applicability of the embedding approach to new fields.