Molecular orbital calculations on dinitrogen trioxide, N₂O₃

Abstract

A minimal Slater basis set molecular orbital calculation on dinitrogen trioxide, N₂O₃, is reported. In the evaluation of integrals, non-NDDO integrals were calculated by the 3G/s expansion technique. Analysis of the wave function obtained shows weak bonding between the nitrosyl and nitro fragments and a very weak attractive interaction between the cis- oxygens. The molecular orbitals for N₂O₃ were expanded in terms of the NO and NO₂ molecular orbitals. A correlation diagram linking the N₂O₃ orbitals with the NO and NO₂ orbitals is presented. The localized molecular orbitals for N₂O₃ are analysed. A configuration interaction calculation involving the ground state and nine doubly excited state configurations is reported. Two excited states have significant contributions. A comparison is made between the results obtained by using a 3G/S expansion and a calculation using a 2G/S expansion.