Pressure-induced structural and electronic transformations of energetic ionic salt hydroxylammonium 3,3′-dinitro-bis-(1,2,4-triazole)-1,1′-diolate

Abstract

This study explores the structural, molecular, and electronic responses of the ionic salt hydroxylammonium 3,3′-dinitro-bis-(1,2,4-triazole)-1,1′-diolate (HDBTD) crystal to external pressure. Utilizing Generalized Gradient Approximation (GGA) in both PBE and Perdew-Wang 91 (PW91) forms, alongside Local Spin Density Approximation (LDA) as per CA-PZ, we compared the computational results with experimental measurements to determine the most accurate method for analyzing the HDBTD crystal. The study reveals the anisotropic nature of the HDBTD crystal under varying pressures up to 200 GPa, with detailed observations on the behavior of lattice constants, unit cell volume, and molecular geometry including bond lengths, angles, and dihedral angles. External pressure was found to induce notable changes in molecular conformation, phase transitions, and the development of denser materials, altering molecular geometry significantly. The formation and breaking of covalent bonds under pressure were highlighted, showing complex effects on the crystal's molecular structure. Furthermore, the impact of pressure on the electronic structure of HDBTD was examined, showing a dynamic change in band gaps and density of states (DOS). The study provides a comprehensive analysis of the HDBTD crystal's response to external pressures, contributing valuable insights into its structural integrity, molecular dynamics, and electronic behavior, thereby enhancing the understanding of its potential applications and reactivity under high-pressure conditions.