Infrared spectra of (NO)(2)(+), (NO)(2)(-), and (NO)(3)(-) trapped in solid neon

New studies of the infrared spectra of the products which result on codepos ition at approximately 5 K of a Ne: NO sample with Ne atoms that have been excited in a microwave discharge have led to new and revised assignments fo r several ionic species. The appearance of the nu(1) absorption of ONNO+ fo r several new species with asymmetric isotopic substitution, but for no sym metrically substituted species, confirms the trans ground-state configurati on for ONNO+. The behavior of a neon-matrix product absorption at 1227.5 cm (-1) parallels that of an argon-matrix absorption at 1221.0 cm(-1) which ha s recently been assigned to trans-ONNO-. The identity of the carrier of a p roduct absorption at 1424.1 cm(-1), contributed by a vibration of two symme trically equivalent NO groups, has not been definitively established. This absorption exhibits complex photodestruction behavior. Three absorptions ar e assigned to cis, cis-(NO)(3)(-), which has C-2v symmetry, with the aid of density functional calculations of the isotopic substitution pattern for t he vibrational fundamentals of this species. Similar calculations of the is otopic substitution patterns for other structures result in poor agreement with the experiments. Photodestruction of cis, cis-(NO)(3)(-) trapped in so lid neon yields the N2O ... NO2- complex. (C) 1999 American Institute of Ph ysics. [S0021-9606(99)01021-1].