Photodissociation dynamics of CO[sub 2] at 157. 6 nm by photofragment-translational spectroscopy

Journal Article · Mon Feb 01 00:00:00 EST 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.464238· OSTI ID:6888285

Stolow, A; Lee, Y T ^[1]

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1. Department of Chemistry, University of California and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

The photodissociation of CO[sub 2] at 157 nm was studied by the photofragment-translational spectroscopy technique. Product time-of-flight spectra were recorded and center-of-mass translational energy distributions were determined. Two electronic channels were observed---one forming O([sup 1][ital D]) and the other O([sup 3][ital P]). With previously determined anisotropy parameters of [beta]=2 for the O([sup 3][ital P]) channel and [beta]=0 for the O([sup 1][ital D]) channel, an electronic branching ratio of 6%[plus minus]2%O([sup 3][ital P]) was obtained, consistent with previous results. The translational energy distribution for the CO([ital v])+O([sup 3][ital P]) channel was very broad (over 30 kcal/mol) and appeared to peak near CO([ital v]=0). The value of [beta]=2 for the O([sup 3][ital P]) channel was confirmed by comparing Doppler profiles, derived from our measured translational energy distribution, with previously measured Doppler profiles. This suggests that the O([sup 3][ital P]) channel arises from a direct transition to an excited triplet state. The O([sup 1][ital D]) channel had a structured time-of-flight which related to rovibrational distributions of the CO product. The influence of the excitation of the CO[sub 2]([nu][sub 2]) bending mode was investigated and shown to have a small but not negligible contribution. Based upon a comparison of our data with a previous vacuum-ultraviolet (VUV) laser induced fluorescence study, we obtain as our best estimate of the vibrational branching ratio, CO([ital v]=0)/CO([ital v]=1)=1.9, for the CO([ital v])+O([sup 1][ital D]) channel.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6888285
• Journal Information: Journal of Chemical Physics; (United States), Vol. 98:3; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CARBON DIOXIDE
DISSOCIATION
CENTER-OF-MASS SYSTEM
ENERGY SPECTRA
FAR ULTRAVIOLET RADIATION
PHOTOCHEMICAL REACTIONS
TIME-OF-FLIGHT METHOD
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
SPECTRA
ULTRAVIOLET RADIATION
664200* - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)