Abstract

The ultrafast internal conversion of photo-excitation energy into directed molecular motion or chemical reaction is a process of fundamental importance in nature. For example, the ultrafast iso-merization of excited rhodopsin molecules is crucial to the first steps in vision, and the rapid quenching of electronic excitation in DNA bases is responsible for their ultraviolet photo-stability. Conical intersections between different electronic states dominate the dynamics by providing the path for electronic relaxation. The dynamics are often initiated by promotion of an electron in a π-orbital of a double bond to an antibonding π^* orbital.

© 2012 Optical Society of America