First-principles study of structural and vibrational properties of crystalline silver azide under high pressure

A detailed first-principles study of the structural and vibrational properties of crystalline silver azide under hydrostatic pressure of 0–500 GPa has been performed with density functional theory in the generalized gradient approximation. The crystal structure is relaxed to allow ionic configurations, cell shape, and volume to change without any symmetry constraints. It is found that the silver azide crystal remains orthorhombic structure with Ibam space group for pressures up to 7 GPa, where there is a transition to an I4/mcm tetragonal symmetry. The lattice parameter and electronic structure are investigated as functions of pressure. The calculated vibrational frequencies at ambient pressure are in agreement with available experimental data. We also discuss the pressure-induced frequency shifts for the internal and lattice modes of silver azide crystal upon compression.

Silver azide attracts scientific and technological interest as an energetic material. There are sufficient difficulties to study it experimentally at extreme conditions due to their explosive nature. This paper presents a detailed first-principles study of the structural and vibrational properties of crystalline silver azide under hydrostatic pressure of 0–500 GPa.Figure optionsDownload as PowerPoint slide