| Abstract
| - The electronic structure and electron affinity of the acetyloxyl radical (CH3COO) were investigated by low-temperature anion photoelectron spectroscopy and ab initio calculations. Photoelectron spectra of the acetateanion (CH3COO-) were obtained at two photon energies (355 and 266 nm) and under three differenttemperatures (300, 70, and 20 K) with use of a new low-temperature ion-trap photoelectron spectroscopyapparatus. In contrast to a featureless spectrum at 300 K, a well-resolved vibrational progression correspondingto the OCO bending mode was observed at low temperatures in the 355 nm spectrum, yielding an accurateelectron affinity for the acetyloxyl radical as 3.250 ± 0.010 eV. This experimental result is supported by abinitio calculations, which also indicate three low-lying electronic states observed in the 266 nm spectrum.The calculations suggest a 19° decrease of the OCO angle upon detaching an electron from acetate, consistentwith the vibrational progression observed experimentally.
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