15min:

JINJUN LIU, Department of Chemistry, University of Louisville, 2320 S. Brook St., Louisville, Kentucky 40292.; DMITRY G. MELNIK AND TERRY A. MILLER, Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, 120 W. 18th Ave., Columbus, Ohio 43210.

The previously obtained ²A'- ²A'' and ²A'- ²A' laser-induced fluorescence (LIF) spectra of jet-cooled cyclohexoxy radical (c-C₆H₁₁O) have been analyzed and simulated using the coupled-two-state model presented in the preceding talk. The rotational and fine structure of the nearly degenerate ²A'' and ²A' states is reproduced using one set of molecular constants including rotational constants, spin-rotation constants, effective spin-orbit constants (a _e d) and the vibronic energy separation between the two states ( E). While the energy level structure could be reproduced by only effective spin-rotation constants (without the spin-orbit constant), the spin-orbit interaction introduces transitions that have no intensity using the separate-states asymmetric rotor model. Rotational and fine-structure analysis using the two-state model has proven to be an effective method to separate the first order electron-spin-molecular-rotation constants from the effective spin-rotation constants, and to decouple the spin-orbit splitting (a _e d) and the vibronic energy separation ( E), both of which contribute to the experimentally observed energy separation between the two coupled states ( E ^- ). Isopropoxy (discussed in the preceding talk), cyclohexoxy, and other molecules in nearly degenerate electronic states provide unique cases bridging the gap from symmetrically degenerate states, e.g., ground ²E state of methoxy, and the Born-Oppenheimer limit of unperturbed electronic states.