Density Functional Study of the Electronic, Bonding, Elastic and Infrared Properties of Tetragonal H2O2 Ice

Hydrogen peroxide is one of the most important commercially used oxidant and exists widely in the environment. It crystallizes in a tetragonal phase via hydrogen bond at around −0.89 °C. However, many of its fundamental properties are still not well studied. To investigate systems containing hydrogen bond, van der Waals correction must be considered. In this work, we tested a series of local and non-local van der Waals corrections within the frame of density functional theory. The optPBE-vdW and the vdW-DF-CX functionals are found to be the best ones based on the relaxed lattice parameters. Then the electronic, bonding, elastic, infrared, piezoelectric and dielectric properties are studied and discussed. The results reveal that tetragonal H2O2 is an indirect band gap insulator. Bond critical point analysis, reduced density gradient analysis and crystal orbital Hamilton population analysis uncover that the H-O···H bonds are moderate hydrogen bonds, which contribute most to the formation of the crystal. The interactions between the O atoms of neighbouring H2O2 molecules also have a bit contribution. Elastic stability of tetragonal H2O2 is confirmed and its elastic anisotropy is illustrated by directional bulk and shear moduli. The vibrational modes at the Brillouin zone center are assigned, and their frequencies and eigen-displacements are calculated. Additionally, its infrared spectrum is simulated. Its Born effective charges, piezoelectric and dielectric coefficients are also obtained and discussed.