Theory of large angle elastic differential cross sections for complex optical potentials: Semiclassical calculations using partial waves, l windows, saddles, and poles

Publisher Website
Google Scholar
Abstract
Four semiclassical (WKB) theories have been used to calculate the large angle elastic scattering for a strongly absorptive complex optical potential modeled on Li+HBr. Two theories—the partial wave and l‐window formalisms—use first‐order single turning point WKB phase shifts for a large number of discrete (integral) angular momenta. The other two theories involve saddle point evaluations of background and subamplitude contour integrals, together wth WKB calculations of the residues and positions of complex angular momentum poles of the S matrix. There are large numerical discrepancies in the differential cross sections at backward angles between the two real angular momentum and the two complex angular momentum theories. Reasons for these discrepancies are analyzed. The complex angular momentum cross sections are more accurate than those computed from the real angular momentum theories and agree closely with l‐window calculations using accurate quantum phase shifts.

This publication has 26 references indexed in Scilit: