QUANTUM DYNAMICAL STEREOCHEMISTRY OF ATOM-DIATOM REACTIONS

We have used density matrix techniques and angular momentum algebra to obtain quantum-mechanical equations describing the dynamical stereoch emistry of the atom-diatom reaction A + BC reversible arrow AB + C. Th e relative motions of reagents and products are specified by four vect ors: rotational angular momenta of diatomic molecules and relative Vel ocities of reagents and products. Our equations show how the correlati ons between the spatial distributions of these four vectors are relate d to the scattering matrix determined in quantum scattering calculatio ns. We present three different expressions for the four-vectors correl ation. One of them is appropriate to the helicity representation of th e scattering matrix, while the others are appropriate to the orbital a ngular momentum representation with either space-fixed or body-fixed r eference frames. The formulation adopted allows for a rigorous compari son between theory and experiment. It takes mixed quantum-mechanical s tates and unobserved quantum-numbers into account, and all vector dist ributions are expressed in terms of measurable quantities (scattering angles and polarization moments of rotational angular momenta). Explic it expressions for most of the lower-order vector correlations obtaine d by direct reduction of the four-vectors correlation formulas are als o presented. (C) 1997 American Institute of Physics.