ELECTRONIC STRUCTURE OF DIVALENT METAL AZIDES

Abstract

Ion-molecular metal azides are well known because of their high reactivity, and nowadays they are widely used as energetic materials. Despite the large amount of experimental data exists on such kind compounds, the number of theoretical studies is still not so large. The aim of the present work is to study of the electronic structure of Me(N3)2 compounds, where Me=Sr, Ca, Cd, Hg. All the calculations have been carried out within the framework of the density functional theory with the use of the numerical pseudo-atomic orbitals basis. The results of the band structure calculations are presented in the work together with a maps of total and partial electronic density; the data on Cd(N3)2 and α-Hg(N3)2 are presented for the rst time. The values of band gaps calculated are in good agreement with those obtained by other authors or estimated in the experiments. The all the crystals under consideration, except of α-Hg(N3)2, are predominantly ionic compounds with a relatively small fraction of the covalent bonding. The overall structure of the valence band spectra, as well as the character of conduction band bottom, is similar to other heavy metal azides. The comparative analysis of the data on band gaps led to the conclusion about lesser stability of the heavy metal azides than that of the second group metal azides, what is also conrmed by the experimental data