ChemInform Abstract: Inversion Potentials in the Ground and Excited Electronic States of 9, 10-Dihydroanthracene as Probed by the Absorption and Fluorescence Spectra of Jet-Cooled Molecules.

The inversion potentials in the ground and the lowest excited singlet states of 9,10‐dihydroanthracene were deduced from the fit of the absorption and fluorescence spectra of jet‐cooled molecules to model potentials. The barrier height in the ground state (615 cm−1 ) is substantially larger than in the excited state (80 cm−1 ). Correspondingly, the folding angle in the ground state is smaller (144.6° vs 164.1°). Comparison of the calculated line intensities with the experimental absorption spectrum indicates that the transition dipole moment is dependent on the nuclear coordinate of the inversion mode. The measured quantum yield of the single vibronic level fluorescence is essentially independent of the quantum number and the symmetry of the inversion level excited.