MTEF!2!1!+- % feaagCart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLD... This chapter illustrates one application of the R-matrix approach to electron collisions with diatomic molecules. The \\( He_2^ + \\) cation is the chosen ......