			15min:

COMBINATION BANDS BETWEEN 2900 AND 3600 CM^-1 OF CYCLIC O₄ CATION TRAPPED IN SOLID NEON.

MARILYN E. JACOX AND WARREN E. THOMPSON, Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8441.

The infrared spectrum of cyc-O₄⁺ trapped in solid neon includes a group of combination bands built on ( ₁ + ₅) of ground-state cyc-O₄⁺. Each peak lies close to a counterpart previously reported in a study of the infrared laser photodissociation spectroscopy of a mass-selected molecular beam. This agreement is consistent with the vibrational assignment of three low-frequency modes of cyc-O₄⁺ that was proposed in the earlier study. The spectra obtained for the isotopologues formed by the substitution of one or two ¹⁸O₂ moieties suggest the occurrence of interaction with a nearby excited electronic state.