THE VIBRATIONAL-SPECTRA OF MOLECULAR-IONS ISOLATED IN SOLID NEON .11. NO2+, NO2-, AND NO3-

When a Ne:NO2 or a Ne:NO:O2 sample is codeposited at approximately 5 K with a beam of neon atoms that have been excited in a microwave discharge, infrared absorptions of NO2+, NO2-, and NO3- appear. Detailed isotopic substitution studies support the assignment of prominent absorptions to nu3 of NO2+ and NO2+ and of weak to moderately intense absorptions to the nu1 + nu3 combination band of each of these species. When the contribution of anharmonicity is considered, the positions of the NO2+ absorptions are in satisfactory agreement with the values for the stretching fundamentals obtained in a recent gas-phase study of that species. When the sample is exposed to 240-420 nm mercury-arc radiation, the initially present absorptions of NO3- trapped in sites with a small residual cation interaction diminish in intensity, and the unsplit nu3(e') absorption of isolated NO3- grows. The mechanism responsible for this growth in the absorption of isolated NO3- is considered.