Femtosecond excited state studies of the two-center three-electron bond driven twisted internal charge transfer dynamics in 1,8-bis(dimethylamino)naphthalene

The femtosecond fluorescence upconversion and transient absorption experiments were performed to monitor the photoinduced electronic, geometry, and solvent relaxation dynamics of 1,8-bis(dimethylamino)naphthalene dissolved in methycyclohexane and acetonitrile. It is concluded that the solvent relaxation and vibrational cooling in the lpi* state cannot be seperated in polar solvents, but in apolar solvents a distinct vibrational cooling process in the lpi* state is discerned.