Raman spectroscopy on matrix-isolated No+, No−3 and N2O4 in Ne

Abstract We report Raman spectra of N 2 O 4 isolated in Ne at 9 K. Most lines can be assigned to different configurations of N 2 O 4 but the most intense line is caused by NO + ions of the species NO + NO − 3 ,a surprising result explainable by a special aggregation of NO 2 molecules during condensation, followed by trapping of the dimer at adjacent vacancies.