Abstract
We have applied the diffusion quantum Monte Carlo (DMC) method to
calculate the cohesive energy and the structural parameters of the binary oxides CaO, SrO,
BaO, Sc2O3, Y2O3 and La2O3. The aim of our calculations is to systematically quantify the
accuracy of the DMC method to study this type of metal oxides. The DMC results were
compared with local and semi-local Density Functional Theory (DFT) approximations as
well as with experimental measurements. The DMC method yields cohesive energies for
these oxides with a mean absolute deviation from experimental measurements of 0.18(2)
eV, while with local and semi-local DFT approximations the deviation is 3.06 and 0.94
eV, respectively. For lattice constants, the mean absolute deviation in DMC, local and
semi-local DFT approximations, are 0.017(1), 0.07 and 0.05 Å, respectively. DMC is
highly accurate method, outperforming the local and semi-local DFT approximations in
describing the cohesive energies and structural parameters of these binary oxides.
