Absorption Spectrum of Carbazole in a Fluorene Matrix

The polarized absorption spectrum of carbazole in a single‐crystal matrix of fluorene at about 15°K is reported. Only the lowest‐energy transition of carbazole was studied, transitions to more highly excited states being obscured by the absorption bands of the matrix. The low‐energy transition of carbazole was assigned ${}^1{A}_1{\mathrm{\hspace{0.17em}\leftarrow \hspace{0.17em}}}^1{A}_1$ in agreement with earlier theoretical work. A vibrational analysis of the excited state is reported, and the assigned fundamentals are compared with those of the ground electronic state.