Internal state distributions of CO from HNCO photodissociation

Journal Article · Sat Aug 01 00:00:00 EDT 1987 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.453215· OSTI ID:6365896

Spiglanin, T A; Perry, R A; Chandler, D W

The internal state distributions of CO produced by photodissociation of HNCO at 1930 (230.1 nm) and at 10 200 cm/sup -1/ (193.3 nm) in excess of the dissociation energy are determined from multiphoton ionization spectra of the CO fragment measured under collision-free conditions. The rotational state distribution of the CO produced at the lower photolysis energy is characterized by a temperature of (491 +- 23) K. The rotational state distribution of CO produced by photodissociation at the higher photon energy in not well characterized by a temperature. This latter distribution has maximum population near J = 37, extends beyond J = 65, and accounts for --20% of the available energy in excess of that necessary to rupture the HN--CO bond. An impulsive dissociation model assuming that dissociation occurs from an excited HNCO complex containing a nonlinear N--C--O configuration accounts for the average CO rotational excitation while phase-space theory does not agree with the observed distributions. Fitting a semiclassical model to the data using a logically constructed potential energy surface and a ground-state-dependent function provides a useful parametrization for the impulsive dissociation. Although not absolute, this analysis suggests that the dissociation occurs directly on a repulsive excited state potential energy surface.

• Research Organization: Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550
• OSTI ID: 6365896
• Journal Information: J. Chem. Phys.; (United States), Vol. 87:3
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON MONOXIDE
ROTATIONAL STATES
ISOCYANIC ACID
PHOTOLYSIS
DISSOCIATION
DISTRIBUTION
CARBON COMPOUNDS
CARBON OXIDES
CARBONIC ACID DERIVATIVES
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
ENERGY LEVELS
EXCITED STATES
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
400500* - Photochemistry