Vibronic coupling in inorganic systems: Photochemistry, conical intersections, and the Jahn–Teller and pseudo-Jahn–Teller effects

Vibronic coupling effects in inorganic systems are of great importance in a variety of scientific fields. Such effects involve a breakdown of the Born-Oppenheimer approximation and the separation of electronic and nuclear motion. We present the basic background theory involved in this, including a discussion of conical intersections, Jahn-Teller vibronic coupling, and pseudo-Jahn-Teller vibronic coupling. In addition to reviewing the importance of vibronic coupling in photochemistry in general, we also review some of the more important computational contributions to inorganic photochemistry. By way of examples, we present several case studies from our own recent work highlighting the issues involved in computational modeling of vibronic coupling effects in inorganic chemistry. These include the computation of coupled Jahn-Teller potential energy surfaces in binary transition metal carbonyl photodissociation, and ultrafast radiationless relaxation of the generated unsaturated metal carbonyl; semi-classical and quantum wave packet dynamics simulations of this relaxation process; analysis of the pseudo-Jahn-Teller effect in ammonia, and an edge-sharing bimetallic bioctahedral complex; and finally the photochemical izomerization of a platinum-amido pincer complex from mer to fac that involves a general nonsymmetry imposed conical intersection along the reaction path. © 2010 Elsevier Inc.