Spectroscopic data on nuclear configuration of dibenzo-p-dioxin in S0, S1, and T1 electronic states

Abstract There is no common opinion about the nuclear configuration pattern of the dibenzo- p -dioxin (DD) molecule in the ground electronic state S 0 –whether its configuration is planar or non-planar, as in the “butterfly” form. In this work, we have analyzed several spectroscopic data (on infrared and Raman spectra, vibronic structure of the singlet electronic excited state S 1 and the phosphorescence spectra) considering the selection rules. These data point to the plane configuration of DD in all (S 0 , S 1 , and triplet T 1 ) electronic states. The S 1 state is found to be due to g-type symmetry.