dc.creator Tao, C. en_US dc.creator Deselnicu, M. en_US dc.creator Mukarakate, C. en_US dc.creator Reid, S. A. en_US dc.creator Schmidt, Timothy W. en_US dc.creator Kable, Scott H. en_US dc.date.accessioned 2008-01-12T13:02:38Z dc.date.available 2008-01-12T13:02:38Z dc.date.issued 2006 en_US dc.identifier 2006-FB-04 en_US dc.identifier.uri http://hdl.handle.net/1811/30815 dc.description Author Institution: Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881; School of Chemistry, University of Sydney, NSW 2006, Australia en_US dc.description.abstract We report a comprehensive new study of the electronic spectroscopy of the A$^{1}B_{1}$-X$^{1}A_{1}$ system of CCl$_{2}$ in the region 400-600 nm. The spectra were measured under jet-cooled conditions using a pulsed discharge source, and rotationally analyzed to yield precise values for the band origins and $A$ rotational constants. As described by Kable and co-workers,} the spectrum can be separated into three distinct regions. Region 1, lying below 20300 cm$^{-1}$, displays regular vibrational structure, and a Dunham expansion fit of the band origins for the C$^{35}$Cl$_{2}$ and C$^{35}$Cl$^{37}$Cl isotopomers reproduces the experimental term energies to within a standard deviation of $<$ 1 cm$^{-1}$. In region 2, lying between 20300 cm$^{-1}$ and roughly 21500 cm$^{-1}$, the rotational structure of the bands is largely unperturbed; however, vibrational mixing is extensive due to near resonances among the states 1$^{n}$2$^{m}$ having the same polyad number $p$=$2n$+$m$. Above 21500 cm$^{-1}$ (Region 3), the rotational structure of the bands changes markedly, such that above 22500 cm$^{-1}$ only subbands terminating in $K_{a}^{\prime}$ = 0 appear strongly in the spectra, indicating that the Renner-Teller (RT) intersection has been exceeded. In this talk, we will focus on the correlation of spectra and lifetime measurements; as found for other simple carbenes, the approach to the RT intersection is evidenced in a pronounced lifetime lengthening for states with $K_{a}^{\prime}$ $>$ 0. The measured $A$ rotational constants exhibit a sudden and significant increase in the vicinity of the barrier. We will also compare our lifetime measurements with previous experimental results. Good agreement is found with a previous matrix isolation study when accounting for matrix effects; however, our lifetimes are not in good agreement with most previous gas-phase studies. en_US dc.language.iso English en_US dc.publisher Ohio State University en_US dc.title FLUORESCENCE EXCITATION SPECTROSCOPY AND LIFETIMES OF THE A$^{1}B_{1}$-X$^{1}A_{1}$ SYSTEM OF CCl$_{2}$ en_US dc.type article en_US
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