Photodissociation Dynamics of the Ethoxy Radical Investigated by Photofragment Coincidence Imaging

Abstract

The photodissociation dynamics of the ethoxy radical (CH 3 CH 2 O) have been studied at energies from 5.17 to 5.96 eV using photofragment coincidence imaging. The upper state of the electronic transition excited at these energies is assigned to the C 2 A′′state on the basis of electronic structure calculations. Fragment mass distributions show two photodissociation channels, OH + C 2 H 4 and CH 3 + CH 2 O. The presence of an additional photodissociation channel, identified as D + C 2 D 4 O, is revealed in time-of-flight distributions from the photodissociation of CD 3 CD 2 O. The product branching ratios and fragment translational energy distributions for all of the observed mass channels are nonstatistical. Moreover, the significant yield of OH + C 2 H 4 product suggests that the mechanism for this channel involves isomerization on the excited-state surface. Photodissociation at a much lower yield is seen following excitation at 3.91 eV, corresponding to a vibronic band of the B 2 A′ r X 2 A′′ transition.

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