Electronic excitation of the b 3Σu+ state of H2 by electron impact using the method of continued fractions

The method of continued fractions (MCF) of Horacek and Sasakawa is applied for the first time to the study of low-energy electron scattering by linear molecules at the two-state close-coupling level. In particular, we have calculated the excitation cross sections for the transition X 1Σg+ → b 3Σu+ in H2 for incident energies from near threshold to 40 eV. In contrast to the early two-state studies of Chung and Lin, in this work no orthogonality constraint between the bound and continuum orbitals is imposed and the one-electron exchange terms are considered explicitly. The calculated cross sections are in very good agreement with the available experimental data and with some recent theoretical results. (author)