Laser-induced fluorescence spectroscopy of the {tilde B};{sup 2}{Pi}{endash}{tilde X};{sup 2}A{sup {double_prime}} band system of HCCO and DCCO
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551 (United States)
The electronic spectroscopy of the {tilde B}&hthinsp;{sup 2}{Pi}{endash}{tilde X}&hthinsp;{sup 2}A{sup {double_prime}} band system of the ketenyl radical, H(D)CCO, is investigated using laser-induced fluorescence (LIF) in a free-jet environment. Vibronically resolved excitation spectra for HCCO are obtained from 33&hthinsp;400 cm{sup {minus}1} to 35&hthinsp;100 cm{sup {minus}1}; at higher energies the LIF spectra cutoff due to a rapid increase in the rate of predissociation. The parallel transitions from K{sub a}{sup {double_prime}}=1 in the ground state to the spin-orbit levels, {sup 2}{Pi}{sub 3/2} and {sup 2}{Pi}{sub 1/2}, of the origin of the {tilde B} state are completely rotationally resolved for both HCCO and DCCO. Four other parallel transitions originating from K{sub a}{sup {double_prime}}=0 in the ground state and terminating on levels of {Sigma} vibronic symmetry are observed and assigned to the two pairs of {Sigma} states derived from one quantum of excitation in each of the Renner{endash}Teller active modes, the CCO and CCH(D) bend. Rotational analysis provides effective rotational constants and spin-rotation (orbit) couplings for each of these levels. In addition to the Renner{endash}Teller and spin-orbit couplings, there is substantial evidence for additional perturbations among the low-lying bending levels in the {tilde B}&hthinsp;{sup 2}{Pi} state of ketenyl. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 347039
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 14 Vol. 110; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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