First-principles study of the electronic, vibrational, thermodynamic properties and phase stability of orthorhombic KClO₄ under pressure

The purpose of this study is to deeply understand the basic physical properties of potassium perchlorate (KClO₄) as a typical ionic energetic material under pressure. KClO₄ Received attention for its widespread use in explosives, fireworks, safety matches and rocket propellants. In this paper, we systematically study the basic physical properties of KClO₄ under 0–20 GPa pressure, including electrons, mechanical, vibrations, and thermodynamic parameters, based on density functional theory (DFT). The accuracy of the calculations was verified by optimizing the lattice parameters of the crystal structure and comparing them with previous experimental values. Electronic structure analysis revealed that KClO₄ is a broadband gap nonconductor. Electronic density of states (DOS) analysis revealed strong covalent bonding between Cl–O bonds. Based on the phonon information, this study calculates the thermodynamic properties of KClO₄ and analyzes a function of the relevant thermodynamic quantities under pressure. Combined with the structural phase transition phenomena observed in high pressure experiments, we analyze the dynamic and mechanical instability. These analyses help to understand the behavior of KClO₄ under high pressure conditions and are crucial for its application in energetic materials.