Emission spectroscopy of photodissociating molecules: a collinear model for CH/sub 3/I and CD/sub 3/I

Journal Article · Thu Oct 09 04:00:00 EDT 1986 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100412a027· OSTI ID:6909235

Sundberg, R L; Imre, D; Hale, M O; Kinsey, J L; Coalson, R D

The photodissociation of CH/sub 3/I and CD/sub 3/I is treated in a pseudolinear triatomic model involving the electronic ground state and a single excited electronic state. Potential energy surfaces were obtained for these two electronic states which agree with experimental data on the absorption spectrum, the Raman or emission spectrum, and the CH/sub 3/ or CD/sub 3/ final product-state distribution. The eigenvalues and eigenfunctions of the ground electronic potential are calculated and agree to within 1% of experimentally measured values. A Fermi resonance between the C-I stretch and CD/sub 3/ umbrella modes in CD/sub 3/I causes a serious perturbation in the shape of the vibrational wave functions. The excited potential energy surface is fit to experimental data by using semiclassical wavepacket dynamics techniques to calculate the absorption and emission spectra. Wavepacket trajectories on the excited surface show the nuclear motion of the molecule during dissociation: at short times the motion is mainly extension of the CI bond, and at later times the CH/sub 3//CD/sub 3/ fragment relaxes from a tetrahedral to a planar configuration. Allowing the wavepacket to propagate to large times gives the final-state distributions for the CH/sub 3/ and CD/sub 3/ fragments which are in qualitative agreement with experimental results.

• Research Organization: Massachusetts Institute of Technology, Cambridge
• OSTI ID: 6909235
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 90:21; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
CHEMICAL REACTIONS
DATA
DECOMPOSITION
DEUTERIUM COMPOUNDS
EIGENFUNCTIONS
EIGENVALUES
ENERGY LEVELS
EXCITED STATES
FUNCTIONS
GROUND STATES
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
IODINATED ALIPHATIC HYDROCARBONS
MATHEMATICAL MODELS
MECHANICS
METHYL IODIDE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
POTENTIALS
QUANTUM MECHANICS
THEORETICAL DATA
WAVE FUNCTIONS