FUMIE X. SUNAHORI, XIAOPENG ZHANG AND DENNIS J. CLOUTHIER, Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055.

Laser-induced fluorescence spectra of jet-cooled HCP+ and DCP+ have been obtained with the pulsed discharge technique using HCP/DCP and argon precursor mixtures. Most of the excited state vibrational fundamentals have been observed and a set of vibrational constants obtained. High resolution spectra of the 2 Pi3/2 components of the 000 bands of both isotopomers have been recorded, and these spectra show resolved phosphorus hyperfine structure which allowed the determination of the excited state Fermi contact parameter. The B values were used to obtain the ground and excited state effective geometric parameters as r0''(CH) = 1.077(2) Å, r0''(CP) = 1.6013(3) Å, r0'(CH) = 1.082(2) Å and r0'(CP) = 1.5331(3) Å. The ground state vibrational energy levels reported in the literature were fitted to a Renner-Teller hamiltonian that included the effects of angular momentum coupling as well as spin-orbit, vibrational anharmonicity and Fermi resonance effects.