BEYOND STATE-TO-STATE DIFFERENTIAL CROSS-SECTIONS - DETERMINATION OF PRODUCT POLARIZATION IN PHOTOINITIATED BIMOLECULAR REACTIONS

We derive a closed-form expression for the angular momentum polarizati on (polarization parameters) of the velocity distribution of the AB(v' ,J') product formed by the reaction sequence AX + hv --> A + X followe d by A + BC(v,J) --> AB(v',J') + C. Although in general (2J' + 1)2 par ameters are needed to describe the polarization of an arbitrary ensemb le of diatomic molecules in a rotational state J', we show that the po larization of the velocity distribution of the AB(v',J') product can b e completely specified by 5J' dynamically significant polarization par ameters. This reduction in the number of degrees of freedom is achieve d by introducing a frame of reference we call the stationary-target fr ame. If the correlation between the relative velocities of the reactan ts and products and J' is described with respect to this frame, the po larization-dependent velocity distribution may be written in terms of the 5J' polarization-dependent state-to-state differential cross secti ons d sigma(k0)/d Omega(r), (k even), d sigma(kl)/d Omega(r), and d si gma(k2)/d Omega(r), for which 0 less than or equal to k less than or e qual to 2J'.