PHOTOELECTRON SPECTROSCOPY AND DYNAMICS OF ICN$^{-}$
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Date
2009
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Publisher
Ohio State University
Abstract
We report the photoelectron spectrum of ICN$^{-}$ and preliminary UV photodissociation studies of ICN$^{-}$. Because CN behaves like a pseudo-halogen, we compare our results to previous spectroscopic and dynamical work on dihalides, such as I$_{2}^{-}$, IBr$^{-}$, and ICl$^{-}$. The photoelectron spectrum of ICN$^{-}$ resembles that of IBr$^{-}$ with transitions to the ground electronic state and two $^{3}\Pi$ excited states. The transition to the ground electronic state of ICN is broad (FWHM $\approx$ 0.75 eV) and structureless which corresponds to accessing high lying vibrational states. Transitions to the excited states are narrow and spaced by 0.13 eV. A complete analysis of the photoelectron spectrum is underway to determine the structure and energetics of ICN$^{-}$ and neutral ICN. In addition, preliminary nanosecond studies of ICN$^{-}$ UV photodissociation are reported. In these two-photon experiments, one photon dissociates ICN$^{-}$ and the second photon detects anionic products via photoelectron spectroscopy. Following excitation ($\lambda$ = 260 nm) to a dissociative electronic state of ICN$^{-}$, we observe two anionic photoproducts: I$^{-}$ and CN$^{-}$. The presence of both photoproducts could be a result of a non-adiabatic transition midway through photodissociation or excitation to two different anionic states which asymptotically correlate to distinct products. Currently, time-resolved photoelectron studies are underway to determine the actual dissociation pathway. This research is being funded by NSF and AFOSR.
Description
Author Institution: JILA, Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder; CO 80309