Beckman Fellow 1999-00

Todd J. Martinez


First Principles Quantum Photodynamics

A long-standing dream of theoretical chemistry has been to compute reaction dynamics from first principles, i.e. without empirical input. This goal has been partially achieved for the special case of reactions where atomic motion can be described completely classically and which occur entirely on the ground electronic state. However, these restrictions preclude investigation of a large part of chemistry, e.g. photochemistry, electron transfer, proton transfer, and chemistry at very high pressures and temperatures. A detailed understanding of these processes is crucial indeed; three of the most common forms of energy (light, mechanical, and electrical) which can be harnessed to induce chemistry are represented among them.

The research of Professor Martínez focuses on first-principles descriptions of chemical reactions that involve these intrinsically quantum mechanical effects. He has developed new approaches which make this possible and demonstrated their effectiveness on fundamental photochemical and proton transfer reactions. During his Center appointment, he will extend these methods to incorporate condensed phase environments and metal centers. New multi-scale representations of electronic wavefunctions and intermolecular forces will be explored to accomplish this. His primary applications will be to cis-trans photoisomerization and metal activation of C-H bonds. Photoinduced isomerization is the first step in vision and also provides a possible route to optical memory devices and photochromic switches. The metal activation of C-H bonds allows for selective functionalization of organic molecules, but is not yet practical because the fundamental mechanisms are poorly understood. Elucidating the general mechanisms involved in these reactions and the influence of solvent may lead to important insights that will point to improvements in the efficiency of these processes.