DFT Study of Dioxidine Oligomer Formation in the Gas Phase and CO2 Environment

This study carries out calculations of molecular clusters of dioxidine and dioxidine complexes with carbon dioxide (CO2) using the density functional theory (DFT) method with B3LYP5 parameterization. Based on the obtained data, a model for the phase transition of dioxidine is developed, including the formation of triclinic and monoclinic crystal structures, utilizing a kinetic model of nucleation. The optimized structures of the molecular clusters of dioxidine correspond to the molecular packing of triclinic and monoclinic crystal forms. The energies of these clusters and the dioxidine–CO2 complexes are compared with the experimental data on the phase composition of dioxidine samples during its cryochemical modification using CO2 as the carrier gas.