Fast beam studies of NCO free radical photodissociation

Journal Article · Thu Oct 01 04:00:00 EDT 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463989· OSTI ID:7082456

Cyr, D R; Continetti, R E; Metz, R B; Osborn, D L; Neumark, D M ^[1]

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

The spectroscopy and dissociation dynamics of the NCO radical have been investigated by applying fast radical beam photodissociation spectroscopy to the {ital {tilde B}} {sup 2}{Pi}{l arrow}{ital {tilde X}} {sup 2}{Pi} electronic transition. Measurements of the photodissociation cross section as a function of dissociation wavelength show that even the lowest vibrational levels of the {ital {tilde B}} {sup 2}{Pi} state predissociate. Analysis of fragment kinetic energy release reveals that the spin-forbidden N({sup 4}{ital S})+CO({sup 1}{Sigma}{sup +}) products are produced exclusively until 20.3 kcal/mol above the origin, at which point, the spin-allowed N({sup 2}{ital D})+CO product channel becomes energetically accessible. The spin-allowed channel dominates above this threshold. By determining the location of this threshold, we obtain a new {Delta}{ital H}{sub {ital f}}{sup 0} for NCO of 30.5{plus minus}1 kcal/mol, several kcal/mol lower than the previously accepted value.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7082456
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 97:7; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
BEAMS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMISTRY
CROSS SECTIONS
DISSOCIATION
ELECTRONIC STRUCTURE
ENERGY
ENERGY LEVELS
EXCITED STATES
FREQUENCY DEPENDENCE
GROUND STATES
KINETIC ENERGY
MOLECULAR BEAMS
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMISTRY
RADICALS
SPECTROSCOPY
THRESHOLD ENERGY
VIBRATIONAL STATES