OBSERVATION OF THE PF2 RADICAL BY RESONANCE-ENHANCED MULTIPHOTON IONIZATION SPECTROSCOPY

We have observed nine new excited electronic states of the PF2 radical in the wave number range 50 000-71 000 cm(-1) via the two photon reso nance enhancements they provide in mass resolved multiphoton ionizatio n spectroscopy. We also report ab initio calculations which yield opti mized energies, geometries, and vibrational frequencies for the ground states of PF2 and of the PF2+ ion. Energetic considerations, and the observation that the frequencies of the nu(1)' (symmetric stretch) and nu(2)' (bending) modes in these excited states closely parallel those of the ground state ion, lead us to conclude that all nine excited st ates are Rydberg states belonging to series that converge to the groun d state ionization limit. Polarization analyses and band contour simul ations allow us to identify the electronic symmetries of the first two of these newly identified states (B-2(1) and (2)A(1) respectively) an d to provide an estimate of the excited state geometries [r(P-F)approx imate to 1.49 Angstrom angle F-P approximate to 109 degrees].