THE ELECTRONIC SPECTRA OF CRYSTALLINE TOLUENE, DIBENZYL, DIPHENYLMETHANE, AND BIPHENYL IN THE NEAR ULTRAVIOLET

Abstract

The electronic absorption spectra of single crystals of toluene, dibenzyl, diphenylmethane, and biphenyl have been photographed at 20 °K. using polarized light in the range 3000 to 2500 Å. The fluorescence spectrum of biphenyl has also been examined. This is the first time that the excited states of biphenyl analogous to the B2u state of benzene have been observed. The main features of the spectra are similar for all four compounds, and the differences may be understood in terms of the weak coupling between the benzene rings of the "double molecules".