title: Time-dependent pump-probe spectra of NeBr2.
abstract: Time- and frequency-resolved pump-probe measurements on NeBr2 have been performed to better characterize its fragmentation dynamics on the B electronic state for vibrational levels in the energy region of the transition from direct vibrational predissociation to intramolecular vibrational relaxation dynamics. Above nu'=20 of the Br2 stretching mode, it was observed that the dependence of lifetime on the vibrational quantum number deviates from the energy-gap law by leveling off in the range of 10 ps<tau<20 ps. In addition to measuring the appearance of Br2 product state levels, we were able to monitor the decay of the initially excited NeBr2 via B-->E transitions of the complex. These transitions are shifted 20 cm(-1) to lower energy from the free Br2 resonances, indicating an E state Ne-Br2 bond energy of 82 cm(-1). Measurements of NeBr2 vibrational predissociation via the delta nu=-2 channel were also performed for nu'=27, 28, and 29. The closing of the delta nu=-1 channel leads to an increase in the lifetimes of these vibrational levels. A new Nd:yttrium aluminum garnet pumped dual optical parametric oscillator/optical parametric amplifier system is described that allows us to conveniently record time-delayed pump-probe spectra with 2-cm(-1) spectral resolution and 15-ps time resolution.
authors.affiliation: Department of Chemistry and Institute of Surface and Interface Science, University of California, Irvine, California 92697-2025, USA. jcabrera@uci.edu
authors.forename: Jose A
authors.initials: JA
authors.lastname: Cabrera
authors.forename: Craig R
authors.initials: CR
authors.lastname: Bieler
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Olbricht
authors.forename: Wytze E
authors.initials: WE
authors.lastname: van der Veer
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Janda