Signs of Tunneling of (n,π*) Excitation in Fluorescence of cis-Azoalkanes

Abstract

We have shown that tunneling of weak residual localization of (n,π*) excitation on the original nitrogen atom of the azo group between its atoms causes splitting of the level for the excited state into two sublevels with different phase modulation frequencies, symmetries, and orientations of the fluorescence dipole moments relative to the axis of the azo bond. The phase modulation frequency for the lower sublevel of the state, antisymmetric to the direction of the N=N bond, is proportional to the level splitting. The diffuse nature of the emission spectrum from this sublevel is due to the high phase modulation frequency of the state.