Two-photon time-of-flight mass and photoelectron spectra of Xe(2)

Twenty-two band systems of jet-cooled Xe2 between 79200 and 97000 cm-1 involving gerade excited states that dissociate to Xe*(5d), Xe*(6p), Xe*(4f), Xe*(5f), Xe*(9p), and Xe*(6f) have been observed and analyzed, sixteen of them for the first time. In this work, both resonance enhanced multiphoton ionization (REMPI)/time-of-flight (TOF) mass spectrometry and REMPI photoelectron (PE) spectroscopy were employed to investigate Xe2 molecular states by detecting photoions and photoelectrons, respectively. The TOF mass spectrometer provided the necessary degree of mass discrimination to obtain single isotopomer data. Unambiguous vibrational numberings and precise molecular constants for most excited states probed in this work have been established based on measured vibrational isotope shifts. Bond lengths were estimated from Franck-Condon factor intensity simulations, while excited state electronic symmetries were deduced primarily from polarization measurements. Polarization measurements proved to be especially valuable for grouping the band systems in the Xe*(4f, 5f, 9p and 6f) regions together in spite of excessive spectral congestion. The derived molecular constants represent a significant improvement in the current understanding of the electronic structure of Xe2.;The dominant molecular ion-core assignments for each gerade Rydberg state were deduced from the REMPI-PE spectra. The gerade Rydberg state symmetry assignments in the Xe*(6p,5d) region agree well with predictions made from angular momentum arguments. In many instances, REMPI-PES also contain photoelectron peaks attributed to excited atomic fragments formed by Xe 2 excited state predissociation. Autoionization dominate the PE spectra of most of the molecular states (XeXe*(4f, 5f, 9p, and 6f)) located above the first ionization potential of the dimer. Dissociative recombination was also observed for the first time using REMPI-PES when Xe*(nf) (n = 4--8) atomic levels were excited.