title: Determination of the electron affinity of the acetyloxyl radical (CH3COO) by low-temperature anion photoelectron spectroscopy and ab initio calculations.
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 acetate anion (CH3COO-) were obtained at two photon energies (355 and 266 nm) and under three different temperatures (300, 70, and 20 K) with use of a new low-temperature ion-trap photoelectron spectroscopy apparatus. In contrast to a featureless spectrum at 300 K, a well-resolved vibrational progression corresponding to the OCO bending mode was observed at low temperatures in the 355 nm spectrum, yielding an accurate electron affinity for the acetyloxyl radical as 3.250 +/- 0.010 eV. This experimental result is supported by ab initio calculations, which also indicate three low-lying electronic states observed in the 266 nm spectrum. The calculations suggest a 19 degrees decrease of the OCO angle upon detaching an electron from acetate, consistent with the vibrational progression observed experimentally.
authors.affiliation: Department of Physics, Washington State University, 2710 University Drive, Richland, Washington 99354, USA.
authors.forename: Xue-Bin
authors.initials: XB
authors.lastname: Wang
authors.forename: Hin-Koon
authors.initials: HK
authors.lastname: Woo
authors.forename: Lai-Sheng
authors.initials: LS
authors.lastname: Wang
authors.forename: Babak
authors.initials: B
authors.lastname: Minofar
authors.forename: Pavel
authors.initials: P
authors.lastname: Jungwirth