15min:
INFRARED SPECTRUM OF THE nu1 FUNDAMENTAL BAND OF H3O+.

J. TANG AND T. OKA, Department of Chemistry, The University of Chicago, Chicago, IL 60637.

Infrared spectrum of H3O+ has been observed by a difference frequency laser spectrometer with positive column discharges of H2/O2 gas mixtures, which gave a spectrum remarkably simpler than the previous one with H2/O2/He discharges. After extending the previous assignment of the nu3 fundamental bands to higher J, K transitions, vibration-rotation structures due to the nu1+ \gets 0- and nu1-\gets 0+ bands of H3O+ were identified with the band origins of 3389.66 cm-1 and 3491.17 cm-1, respectively, in the region of the strong nu3\pm\gets 0\pm bands. Molecular constants for the nu1\pm\gets 0\mp bands were obtained by the least-squares fittings for the observed frequencies. Coriolis interactions between the nu1 and nu3 vibrations have been considered to explain some large deviations of the observed transitions from the calculated frequencies in the nu1 and nu3 bands.