Photodissociation dynamics of pyridine

Journal Article · Mon Aug 01 04:00:00 EDT 2005 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.1994849· OSTI ID:20723005

Lin, M -F; Dyakov, Yuri A; Tseng, C -M; Mebel, Alexander M; Sheng, H -L; Lee, Yuan T; Ni, C -K ^[1]

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1. Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, Taiwan (China)

Photodissociation of pyridine, 2,6-d{sub 2}-pyridine, and d{sub 5}-pyridine at 193 and 248 nm was investigated separately using multimass ion imaging techniques. Six dissociation channels were observed at 193 nm, including C{sub 5}NH{sub 5}{yields}C{sub 5}NH{sub 4}+H (10%) and five ring opening dissociation channels, C{sub 5}NH{sub 5}{yields}C{sub 4}H{sub 4}+HCN, C{sub 5}NH{sub 5}{yields}C{sub 3}H{sub 3}+C{sub 2}NH{sub 2}, C{sub 5}NH{sub 5}{yields}C{sub 2}H{sub 4}+C{sub 3}NH, C{sub 5}NH{sub 5}{yields}C{sub 4}NH{sub 2}+CH{sub 3} (14%), and C{sub 5}NH{sub 5}{yields}C{sub 2}H{sub 2}+C{sub 3}NH{sub 3}. Extensive H and D atom exchanges of 2,6-d{sub 2}-pyridine prior to dissociation were observed. Photofragment translational energy distributions and dissociation rates indicate that dissociation occurs in the ground electronic state after internal conversion. The dissociation rate of pyridine excited by 248-nm photons was too slow to be measured, and the upper limit of the dissociation rate was estimated to be 2x10{sup 3} s{sup -1}. Comparisons with potential energies obtained from ab initio calculations and dissociation rates obtained from the Rice-Ramsperger-Kassel-Marcus theory have been made.

• OSTI ID: 20723005
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 5 Vol. 123; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
DISSOCIATION
ENERGY SPECTRA
EXCITED STATES
GROUND STATES
HYDROCYANIC ACID
INTERNAL CONVERSION
METHYL RADICALS
PHOTON-MOLECULE COLLISIONS
PHOTONS
PYRIDINE
REACTION KINETICS