Momir Mališ

Intersystem crossing (ISC) is a very important phenomenon in the photodeactivation of many chemical systems. The spin flip from a singlet to a triplet excitation character is in principle a forbidden transition, but spin–orbit coupling renders the radiationless process possible. (1,2) Due to the low probability, ISC of standard organic molecules without heavy atoms is relatively slow, so that the overall decay after photoexcitation is often dominated by other pathways.