Chergui, Majed2015-09-282015-09-282015-09-28201510.1515/pac-2014-0939https://infoscience.epfl.ch/handle/20.500.14299/119298WOS:000358056500003The advent of ultrafast laser spectroscopy has allowed entirely new possibilities for the investigation of the ultrafast photophysics of inorganic metal-based molecular complexes. In this review we show different regimes where non-Kasha behavior shows up. We also demonstrate that while ultrafast intersystem crossing is a common observation in metal complexes, the ISC rates do not scale with the magnitude of the spin-orbit coupling constant. Structural dynamics and density of states play a crucial role in such ultrafast ISC processes, which are not limited to molecules containing heavy atoms.fluorescence spectroscopyintramolecular relaxationmolecular dynamicsphotochemistrytransition metalsUV-visible spectroscopyXXV IUPAC Photochemistrytext::journal::journal article::research article