On possible absorption effects in elastic scattering of electrons on molecules

Elastic cross sections for positron scattering on noble gases (Ar, Kr) at energies of a few tens of eV exhibit structures which have been attributed to absorption effects. Recent, precise measurements for Ar do not confirm the existence of such effects for electron scattering. Here, we show that previous measurements indicate the existence of an absorption effect for e- + H2 scattering around 60 eV. The reason for this can probably be ascribed to the e--H2 total cross section partitioning scheme, which is more similar to the one for e+-Ar than to the one for e--Ar. (Author)