276-nm absorption band system of m-dichlorobenzene: Vibrational fine structure analysis

The vibrational fine structure accompanying the 276-nm absorption band system (${}^1\text{B}{}_2\text{←}{}^1\text{A}{}_1$) of m-dichlorobenzene (m-DCB) vapor has been reanalyzed. Unambiguous assignments for about 80% of the measured transitions have been presented here. The assignments have been greatly facilitated by the results of band contour analysis as well as Raman and ir data. Vibrational fine structure assignments have led to a determination of excited state fundamentals which are not allowed to appear in single quantum excitation. Wherever possible, a close correspondence has been established between the various normal modes of m-DCB and benzene.