Anion photoelectron spectroscopy of carbon hydride clusters C2n+1H- (n=1-4)

PHYS 367

Sean M. Sheehan, sheehans@berkeley.edu1, Bradley F Parsons, bfparsons@calmail.berkeley.edu1, Giovanni Meloni, giovanni@radon.cchem.berkeley.edu1, Nadine Wehres2, and Daniel M. Neumark, dneumark@berkeley.edu3. (1) Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, (2) Institut für Physikalische Chemie und Elektrochemie, Heinrich-Heine Universität, Düsseldorf, Germany, (3) Department of Chemistry, University of California, Berkeley, CA 94720
We present results for the anion photoelectron spectroscopy of the odd-numbered carbon monohydride anions C2n+1H- (n = 1-4) using both field free electron time-of-flight spectroscopy and velocity mapped imaging. The anion photoelectron spectrum of C3H- has been published previously; however, this work presents the photoelectron spectrum for C3H- at higher resolution. The current results are the first photoelectron spectra of C5H-, C7H-, and C9H-. For each species we determine the electron affinity for the linear isomers as 1.838 ± 0.015 eV (C3H-), 2.423 ± 0.008 eV (C5H-), 2.821 ± 0.007 eV (C7H-), and 3.104 ± 0.007 eV (C9H-). We observe a cyclic isomer for C5H-, C3C2H and determine the electron affinity to be 2.865 ± 0.010 eV for this isomer. Furthermore, in the photoelectron spectra for every C2n+1H- (n = 1-4) anion, we observe vibrational structure resulting from C-C stretching and C-C-C bending motion in the 2Π neutral ground state. The progressions are consistent with the structural changes between the anion and the neutral ground state. Finally, for each species we observe a higher-lying electronic state that we attribute to the 4Σ- state of the neutral carbon-hydride.

Poster Session
7:30 PM-10:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster

8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Physical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006