Femtochemistry : The Role of Alignment and Orientation

Some aspects of alignment and orientation have been considered for femtochemistry experiments. Elementary theoretical descriptions of the time evolution of alignment and angular momenta have been discussed and related to the radial and angular parts of the potential-energy surface. Applications to ICN unimolecular dissociation, H + C 0 2 ‘oriented’ bimolecular reaction, and crossings between different potential-energy curves in alkali-metal halide reactions (M + X ) are given. Emphasis is on the femtosecond dynamics of the transition-state region and the clocking of fragment separation in real time.