Slow photoelectron velocity-map imaging spectroscopy of the n-methylvinoxide anion.

High resolution photoelectron spectra of the n-methylvinoxide anion and its deuterated isotopologue are obtained by slow electron velocity-map imaging. Transitions between the X̃(1)A' anion ground electronic state and the radical X̃(2)A" and Ã(2)A' states are observed. The major features in the spectra are attributed to transitions involving the lower energy cis conformers of the anion and neutral, while the higher energy trans conformers contribute only a single small peak. Franck-Condon simulations of the X̃(2)A" ← X̃(1)A' and Ã(2)A' ← X̃(1)A' transitions are performed to assign vibrational structure in the spectrum and to aid in identifying peaks in the cis-n-methylvinoxy X̃ (2)A" band that occur only through vibronic coupling. The experimental electron affinity and à state term energy are found to be EA = 1.6106 ± 0.0008 eV and T(0) = 1.167 ± 0.002 eV for cis-n-methylvinoxy.