Communication: Ultraviolet photodissociation dynamics of the simplest Criegee intermediate CH{sub 2}OO

Journal Article · Mon Oct 14 00:00:00 EDT 2013 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4824655· OSTI ID:22224135

Lehman, Julia H.; Li, Hongwei; Beames, Joseph M.; Lester, Marsha I. ^[1]

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1. Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 (United States)

The velocity and angular distributions of O {sup 1}D photofragments arising from UV excitation of the CH{sub 2}OO intermediate on the B {sup 1}A′←X {sup 1}A′ transition are characterized using velocity map ion imaging. The anisotropic angular distribution yields the orientation of the transition dipole moment, which reflects the π*←π character of the electronic transition associated with the COO group. The total kinetic energy release distributions obtained at several photolysis wavelengths provide detail on the internal energy distribution of the formaldehyde cofragments and the dissociation energy of CH{sub 2}OO X {sup 1}A′ to O {sup 1}D + H{sub 2}CO X {sup 1}A{sub 1}. A common termination of the total kinetic energy distributions, after accounting for the different excitation energies, gives an upper limit for the CH{sub 2}OO X {sup 1}A′ dissociation energy of D{sub 0}≤ 54 kcal mol{sup −1}, which is compared with theoretical predictions including high level multi-reference ab initio calculations.

• OSTI ID: 22224135
• Journal Information: Journal of Chemical Physics, Vol. 139, Issue 14; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
ANISOTROPY
DIPOLE MOMENTS
DISSOCIATION
DISSOCIATION ENERGY
ENERGY SPECTRA
EXCITATION
EXCITED STATES
FORMALDEHYDE
KINETIC ENERGY
PHOTOLYSIS
PHOTON-MOLECULE COLLISIONS