Improving the Description of Nonmagnetic and Magnetic Molecular Crystals via the van der Waals Density Functional

TL;DR

This paper improves the description of nonmagnetic and magnetic molecular crystals by implementing a stress tensor formulation for the van der Waals density functional with spin-polarization correction, leading to better structural predictions.

Contribution

The authors derived and implemented a stress tensor formulation for vdW-DF with spin-polarization correction, enhancing the accuracy of molecular crystal structure predictions.

Findings

vdW-DF with GC improves cell parameter predictions

Original vdW-DF accurately predicts solid oxygen structure

Structural parameters align well with experimental data

Abstract

We have derived and implemented a stress tensor formulation for the van derWaals density functional (vdW-DF) with spin-polarization-dependent gradient correction (GC) recently proposed by the authors [J. Phys. Soc. Jpn. 82, 093701 (2013)] and applied it to nonmagnetic and magnetic molecular crystals under ambient condition. We found that the cell parameters of the molecular crystals obtained with vdW-DF show an overall improvement compared with those obtained using local density and generalized gradient approximations. In particular, the original vdW-DF with GC gives the equilibrium structural parameters of solid oxygen in the {\alpha}-phase, which are in good agreement with the experiment.