B-SPLINE METHODS IN R-MATRIX THEORY FOR SCATTERING IN 2-ELECTRON SYSTEMS

The use of B-spline basis sets in R-matrix theory for scattering proce sses has been investigated. In the present approach a B-spline basis i s used for the description of the inner region, which is matched to th e physical outgoing wavefunctions by the R-matrix. Using B-splines, co ntinuum basis functions can be determined easily, while pseudostates c an be included naturally. The accuracy for low-energy scattering proce sses is demonstrated by calculating inelastic scattering cross section s for e(-) colliding on H. Very good agreement with other calculations has been obtained. Further extensions of the codes to quasi two-elect ron systems and general atoms are discussed as well as the application to (multi) photoionization.