The electronic spectroscopy of jet-cooled difluorocarbene (CF{sub 2}): The missing {ital {tilde A}}-state stretching frequencies
- School of Chemistry, University of Sydney, Sydney, New South Wales, 2006 (Australia)
The {ital {tilde A}}({sup 1}{ital B}{sub 1}){l_arrow}{ital {tilde X}}({sup 1}{ital A}{sub 1}) electronic transition of difluorocarbene (CF{sub 2}) has been studied by laser-induced fluorescence spectroscopy in a supersonic free jet and by {ital ab} {ital initio} theoretical methods. The radical was formed by pyrolysis of C{sub 2}F{sub 4} at {similar_to}1000 {degree}C with a heating chamber at the tip of the nozzle just prior to the gas expansion. Fairly complete rotational cooling, but incomplete vibrational cooling allowed the identification of several new hot band transitions. {ital Ab} {ital initio} calculations for the {ital {tilde X}}({sup 1}{ital A}{sub 1}), {ital {tilde a}}({sup 3}{ital B}{sub 1}), and {ital {tilde A}}({sup 1}{ital B}{sub 1}) electronic states were performed using the CASSCF method in conjunction with Dunning`s cc-pVTZ basis set, as well as two smaller sets. The calculations allow us to distinguish between several possible assignments of the observed transitions, and hence determine the vibrational frequencies of the two previously unassigned {ital {tilde A}}-state stretching frequencies: {nu}{sub 3}{sup {prime}}=1180{plus_minus}2 cm{sup {minus}1} and {nu}{sub 1}{sup {prime}}=1011{plus_minus}2 cm{sup {minus}1}. The ordering of these modes is different from that in the ground state ({nu}{sub 1}{sup {double_prime}}{gt}{nu}{sub 3}{sup {double_prime}}) and mechanisms for the switching are discussed.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 122960
- Journal Information:
- Journal of Chemical Physics, Vol. 103, Issue 11; Other Information: PBD: 15 Sep 1995
- Country of Publication:
- United States
- Language:
- English
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