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 (KClO 4) as a typical ionic energetic material under pressure. KClO 4 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 KClO 4 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 KClO 4 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 KClO 4 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 KClO 4 under high pressure conditions and are crucial for its application in energetic materials. The evolution of the structure, electronic, thermodynamic properties, vibrational properties, and stability of potassium perchlorate under pressure. [Display omitted] • Based on density functional theory, the basic physical properties of KClO4 under 0-20 GPa pressure are systematically studied. • The results of electronic property analysis show that KClO4 is a wide-band gap nonconductor and there is a strong covalent bond between Cl-O. • The vibrational modes of KClO4 at different frequencies at 0 GPa were analyzed by phonon calculation. • From the theoretical point of view, the evidence of the structural phase transition of orthorhombic KClO4 under pressure was found. [ABSTRACT FROM AUTHOR]