THE VIBRATIONAL-SPECTRA OF MOLECULAR-IONS ISOLATED IN SOLID NEON .4. NO+, NO-, ONNO+, AND ONNO-

When a Ne:NO sample is codeposited at approximately 5 K with a beam of neon atoms that has been excited in a microwave discharge, photoionization and Penning ionization of the NO lead to the stabilization of both monomer and dimer ions. The most prominent infrared absorption, at 1619.2 cm-1, results from the reaction of NO - with NO or of an electron with (NO)2 to form the charge-delocalized iraws-ONNO- species. The position of the totally symmetric NO-stretching absorption of trans ONNO - can be inferred from observation of a combination band. The infrared absorption of NO + has been detected very close to the gasphase band center. Other infrared absorptions have been tentatively assigned to NO -, cis ONNO -, trans ONNO, and the lowest energy isomer of ONNO +. Comparison of the gasphase vibrational frequencies observed for the weakly bound species cis ONNO and N2O3 with the corresponding frequencies observed in this neon-matrix study suggests that the matrix shifts for the dimer ion absorptions in the mid-infrared probably amount to less than 1%. © 1990 American Institute of Physics.