Nearside—farside theory of elastic angular scattering for strongly absorptive collisions

Abstract

A systematic investigation has been made of ways for combining the method of Yennie, Ravenhall and Wilson (YRW) for the resummation of a partial wave Legendre series with the nearside—farside (NF) angular decompositions of Fuller and Hatchell. Of the resulting four procedures, the most useful one first applies the YRW resummation method m times (m = 0,1,2,…) to the partial wave scattering amplitude, followed by the Fuller NF decomposition. This NF procedure performs best for the physical interpretation of structure in the angular scattering of strongly absorptive elastic collisions. Numerical results from all four NF procedures are reported for a partial wave series possessing a simple parametrized scattering matrix element. The theory and calculations are relevant to atom—atom and atom—molecule elastic scattering in the presence of other open channels, for example, chemical reaction.