Electronic and geometric structure of isomers of nitric acid. DFT quantum chemical calculations

Abstract

Based on the B3LYP/6-311++G(3df,3pd) density functional method, quantum chemical calculations of the electronic structure, geometry, and thermodynamic parameters of eight isomers of nitric acid (three known isomers in the form of peroxynitrous acid ONOOH and five new isomers in the form of oxo-conformation OON(H)O) are presented in the work. The molecular structure of each isomer is characterized by a local minimum on the potential energy hypersurface of the HNO3 molecular system and corresponds to one of its stationary states. A theoretical study of the reactivity of nitric acid oxo-isomers characterized for the first time can provide adequate explanation for experiments on the autocatalytic use of nitric acid vapors in binding molecular nitrogen. The results obtained can be a direction for developing principally new methods to bind atmospheric nitrogen and activate methane, which are fundamental problems in chemical science and technology.