Abstract
The electronic excitation of the repulsive b3 Sigma u+ state of H2 from the ground state is studied using the R-matrix method. Correlation and polarisation effects are included ab initio. Results are compared with other theoretical work. While previous calculations appear to underestimate the cross section, good agreement is obtained with the results of the linear algebraic method and the Schwinger multichannel formulation. The authors also present elastic scattering cross sections in the same approximation and compare the results with other work. They obtain satisfactory agreement with experimental results.