Photochemistry from first principles - advances and future prospects

Detailed simulation of photochemistry poses considerable challenges because quantum mechanical effects are important in determining both the electroni c potential energy surfaces and the subsequent nuclear dynamics. We provide a brief overview of the ab initio multiple spawning (AIMS) method which ad dresses the problem by solving both the electronic and nuclear Schrodinger equations simultaneously, We discuss our recent AIMS simulations of cis-tra ns photoisomerization in ethylene as an example application. The prospects of the method for modeling of photochemistry in large organic molecules and condensed phases are assessed. (C) 2001 Elsevier Science B.V. All rights r eserved.