THE PHOTOELECTRON ANGULAR DISTRIBUTION AS A PROBE OF ENERGETICALLY INDISTINGUISABLE CHANNELS IN PHOTODETACHMENT
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Date
2010
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Publisher
Ohio State University
Abstract
Photoelectron imaging measurements of I$^{-}\cdot$CH$_{3}$CN are presented from the lowest energy I($^{2}$P$_{3/2}$)$\cdot$CH$_{3}$CN channel threshold to 0.3 eV above the I($^{2}$P$_{1/2}$)$\cdot$CH$_{3}$CN threshold. Excitation of the cluster just below the latter threshold leads to competition between direct detachment and the production of a dipole-bound state [I($^{2}$P$_{1/2}$)$\cdot$CH$_{3}$CN]$^{-}$. Subsequent relaxation of the I moiety ($^{2}$P$_{1/2}\rightarrow^{2}$P$_{3/2}$) occurs via autodetachment of the dipole bound electron. However, the autodetached electrons are energetically equivalent to those directly detached via the $^{2}$P$_{3/2}$ channel. While the photoelectron spectrum is insensitive to this phenomenon, the kinetic energy dependence of the photoelectron angular distribution (PAD) of the $^{2}$P$_{3/2}$ channel reflects these dynamics. Dramatic changes are observed within a 100 meV window of the I($^{2}$P$_{1/2}$)$\cdot$CH$_{3}$CN threshold. Although previously unreported, further results are presented that show sharp changes in the PAD are relatively common in I$^{-}\cdot$X cluster anions (X=polar molecule).
Description
Author Institution: Department of Chemistry, Washington University, One Brookings Dr., Campus Box 1134 Saint Louis, Missouri 63130, USA