Geometry and Torsional Motion of Biphenyl in the Ground and First Excited Singlet State

摘要

Biaryl molecules, of which biphenyl is the prototypic example, are of fundamental interest for two reasons. First, they are typically composed of two chromophores coupled by a single C-C bond so their energy levels and dynamical behavior can be thought of in terms of these two interacting moieties. In fact, exciton or exchange interaction between the two halves of the molecules has often been invoked to explain the electronic properties of biaryl molecules. Second, the conformational structure and dynamics of these molecules give insight into the behavior of nonrigid large molecules. These important concerns notwithstanding, a detailed study of the vibronic states of biaryl molecules in general, and biphenyl in particular, is difficult due to the diffuseness of their gas phase spectra. In this paper we report supersonic molecular jet mass selected excitation spectra for biphenyl and a number of its isotopic and chemical derivatives. Keywords: Reprints. (MJM)