ELECTRON HYDROGEN SCATTERING AT INTERMEDIATE ENERGIES

Calculations of 1s --> 1s elastic scattering and 1s --> 2s and 1s --> 2p excitation are reported for the intermediate energy range from 13.6 to 54.4 eV. Different methods have been employed for different intervals of the total orbital angular momentum L: (i) in 0 less-than-or-equal-to L less-than-or-equal-to 4 the new intermediate energy R-matrix method of Burke et al (1987) has been used; (ii) in 5 less-than-or-equal-to L less-than-or-equal-to L(max), where L(max) varies between 10 and 16, coupled pseudostate calculations have been performed using the 1s, 2s, 3sBAR, 4sBAR, 2p, 3pBAR, 4pBAR, 3dBAR, 4dBAR basis of Fon et al (1981); (iii) in L(max) + 1 less-than-or-equal-to L < infinity the plane wave second Born approximation has been used. The second Born approximation has also been employed to provide corrections for angular symmetries omitted in (i) and (ii). Integrated and differential cross sections, and alignment and orientation parameters are presented and compared with experiment. For elastic scattering there is good agreement. For the 1s --> 2s and 1s --> 2p transitions the quality of agreement is not quite so satisfactory with some notable discrepancies appearing, especially at 54.4 eV.