AB-INITIO STRUCTURE AND WAVE-PACKET DYNAMICS OF ICN PHOTODISSOCIATION

We present a time-dependent quantum mechanical calculation of ICN photodissociation in the à continuum, using the ab initio potential surfaces of Morokuma and co-workers [S. Yabushita and K. Morokuma, Chem. Phys. Lett. 175, 518 (1990); Y. Amatatsu, S. Yabushita, and K. Morokuma, J. Chem. Phys, 100, 4894 (1994)]. Five excited state potential energy surfaces are included in this model, 3Π0+, 1Π 1 (A′,A″), and 3Π1 (A′,A″), which are accessed, respectively, by parallel, perpendicular, and perpendicular transitions from the ground state. The calculated absorption spectrum, β parameters, the I/I* branching ratio, and the rotational product distribution are in good agreement with experiment. The I/I* branching ratio for photodissociation from vibrationally excited states of ICN has been calculated. The results are in good agreement with the recent measurements at different vibrational temperatures by Kash and Butler [P. W. Kash and L. J. Butler, J. Chem. Phys. 96, 8923 (1992)] at 249 nm but, interestingly, predict opposite trends at higher and lower excitation energies. © 1994 American Institute of Physics.