The anomalous-diffraction approximation of Van de Hulst is used to derive closed-form expressions for the absorption and extinction efficiencies of the long absorbing cylinder at normal and oblique incidence. The predictions of these expressions are compared with those of the exact theory for cylinders of various sizes, refractive indices, degrees of absorption, and orientations. A correction for the approximate solution at very oblique incidence is suggested.
DAN A. CROSS and PAUL LATIMER, "General Solutions for the Extinction and Absorption Efficiencies of Arbitrarily Oriented Cylinders by Anomalous-Diffraction Methods," J. Opt. Soc. Am. 60, 904-907 (1970)