From Jabłoński To Femtoseconds. Evolution of Molecular Photophysics

A presentation is given, with retrospective commentary, on the ex- perimental and theoretical contributions to key steps in the evolution of the framework of contemporary molecular photophysics from the Jablonski Diagram to femtosecond range excitation phenomena. The distinctive fea- tures of polyatomic molecules separating their behavior from atomic and diatomic molecules are emphasized. Justification is given for the statement that spin-orbital coupling with its relativistic component commonly domi- nates the molecular excitation dynamics of light-(low-Z)-atom molecules. The paper deals with single-photon, single-molecule excitations. Some ex- amples of single-photon, multi-molecule and multi-photon, single-molecule excitation phenomena are listed. A selection of these is made to illustrate the prevalence of femtosecond excitation modes.