Cohesive energy and structural parameters of binary oxides of groups IIA and IIIB from diffusion quantum Monte Carlo

TL;DR

This study demonstrates that diffusion quantum Monte Carlo (DMC) provides highly accurate predictions of cohesive energies and structural parameters for certain binary oxides, outperforming various DFT methods and aligning closely with experimental data.

Contribution

The paper systematically evaluates the accuracy of DMC for binary oxides, showing its superiority over local, semi-local, and hybrid DFT in predicting cohesive energies and lattice constants.

Findings

DMC yields cohesive energies with a mean absolute deviation of 0.18 eV from experiments.

DMC's lattice constant predictions deviate by only 0.017 Å on average.

DMC outperforms DFT methods in accuracy for these oxides.

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, semi-local and hybrid 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, semi-local and hybrid DFT approximations the deviation is 3.06, 0.94 and 1.23 eV, respectively. For lattice constants, the mean absolute deviation in DMC, local, semi-local and hybrid DFT approximations, are 0.017(1), 0.07, 0.05 and 0.04 {\AA}, respectively. DMC is highly accurate method, outperforming the DFT approximations in describing the cohesive energies and structural parameters of these binary oxides.