Product rotational polarization in photon-initiated bimolecular reactions

Abstract

This paper concerns the semiclassical description, calculation and measurement of angular momentum polarization in the products of elementary gas-phase bimolecular reactions. A unified, semiclassical treatment of the centre-of-mass correlated (k,k′,j′) angular distribution involving the reagent and product relative velocity and the product angular momentum vectors is described, and is related to other methodologies already existing in the literature. Explicit expressions are provided enabling experimentalists to extract rotational polarization information from crossed-molecular beam and photon-initiated reaction studies, under a variety of experimental conditions. Furthermore, the strategy developed is well suited to the theoretical calculation of reaction product polarization, in particular, using classical trajectory methods. An illustrative example of such a calculation is presented, and the centre-of-mass polarization data provided is used to simulate the laboratory frame rotational moments that can be determined experimentally using 1+1 Doppler-resolved polarized Laser product probing techniques.