Electron photodetachment from aliphatic molecular anions. Gas-phase electron affinities of methoxyl, tert-butoxyl, and neopentoxyl radicals

Negative Ion Spectroscopy

“…, ,/iI- correction for each is calculated and applied, from which EA(CH30) = 1.570 ± 0.022 e V is obtained, in excellent agreement with the photode tachment results of Janousek et al (52). The lahn-Teller and spin-orbit effects in the neutral CH30 X 2E state are too small to affect the spectrum detectably.…”

“…The progression that begins at -0.97 eV and extends to lower electronic kinetic energy represents a totally symmetric al vibrational sequence characteristic of either the C-O stretch, v3' the symmetric C-H stretch, V I ' or the methyl group umbrella bend, V 2 • Ab initio (51) and CNDO/2 (52) optimizations of the structures of both CH30-and CH30 reveal a substantial increase in the HCH angle upon photodetachment, which suggests that the V 2 umbrella mode will have large off-diagonal Franck-Condon factors in this system. The reduction of vibrational spacings observed upon deuteration indicates the progres sion results from a hydrogen motion, and the energy spacing (1325 ± 30 cm -I in CH30 and 10 1O±30 cm-I in CD30) is more characteristic of a hydrogen bend rather than stretch, in accordance with this same conclu sion reached in the CH30-threshold photodetachment study(52). A small vibrational peak at approximately 1.10 eV electron kinetic energy represents the (v2= I)XiA I CH30-�(P2=0)X2E CH30 transition or hot-band photodetachment.…”

Vibronic structure of alkoxy radicals via photoelectron spectroscopy

“…Consequently, there has been no shortage of experimental work on this ubiquitous radical. Some of the earlier research involved laser magnetic resonance ͑LMR͒, 1 microwave studies, 2 and negative ion photoelectron spectroscopy, 3 as well as numerous fluorescence spectroscopic examinations of the à -X electronic transitions; [4][5][6][7][8][9] however, analysis of much of this data was complicated by the overlap and congestion due to room temperature samples as well as poor resolution. Furthermore, there was no indication of any Jahn-Teller effects that would be expected as a result of both the electronic degeneracy of the 2 E ground state and the high-symmetry C 3v configuration.…”

“…Based on the rotational structure of the spectra, they assign the ground state of ethoxy radical to be 2 AЉ with a low-lying 2 AЈ state, whereas in iso-propoxy radical, the rotational signature of the fluorescence transitions suggests that the symmetry switches to a 2 AЈ ground state with a 2 AЉ first excited state. Aside from the EA determination in the PES study, 25 our understanding of tert-butoxy extends to a structure calculation of the anion and radical 6,20 and measurement of the electron photodetachment cross section of the anion. 6 The suite of alkoxides chosen in this work is of particular interest as a study of substitution effects.…”

“…Aside from the EA determination in the PES study, 25 our understanding of tert-butoxy extends to a structure calculation of the anion and radical 6,20 and measurement of the electron photodetachment cross section of the anion. 6 The suite of alkoxides chosen in this work is of particular interest as a study of substitution effects. Methoxide is a closed-shell anion with C 3v symmetry.…”