Spectroscopic observation of vibrational Feshbach resonances in near-threshold photoexcitation of X-·CH3NO2 (X- = I- and Br-)

Caroline E.H. Dessent, Jun Kim, Mark A. Johnson*

*Corresponding author for this work

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We report the observation of resonance structure in the absorption and X-/NO2- photofragment action spectra of the X- ·CH3NO2 (X- = I- and Br-) complexes in the region above the electron detachment threshold. The resonance structure corresponds to peaks which appear at the onsets for vibrational excitation of the -NO2 wag, scissors, and stretch modes of neutral CH3NO2, the modes which most strongly distort upon electron capture into its π* lowest unoccupied molecular orbital. We attribute the peaks to excitation of vibrational Feshbach resonances of the CH3NO2- transient negative ion, where near-threshold excitation of X- ·CH3NO2 spectroscopically accesses states of the free electron-CH3NO2 system.

Original languageEnglish
Pages (from-to)395-406
Number of pages12
Publication statusPublished - 1 Jan 2000

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