			15min:

A HIGH RESOLUTION STUDY OF THE ELECTRONIC SPECTRA OF CONFORMERS OF 1,3 AND 1,4 DIVINYLBENZENE: UNEXPECTED EXCITED STATE BEHAVIOR.

TRI NGUYEN, JASON W. RIBBLETT AND DAVID W. PRATT, Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260.

The vibrationally resolved S₁ leftarrow S₀ electronic spectra of 1,3- and 1,4-divinylbenzene each exhibited two origin bands that are 800 cm^-1 and 1000 cm ^-1 apart respectively. Intrigued by this observation, we have recorded the different bands at full rotational resolution in a molecular beam. Analyses of these data show that the two bands are the S₁ leftarrow S₀ of the different conformers, cis and trans, in each molecule, which are remarkably far apart. Typically, such systems exhibit more closely spaced origin bands. A model that accounts for this unexpected behavior will be discussed.