ACCURATE VARIATIONAL DETERMINATION OF CONTINUUM WAVE-FUNCTIONS BY A ONE-CENTER EXPANSION IN A SPLINE BASIS - AN APPLICATION TO H-2(+) AND HEH2+ PHOTOIONIZATION

The one-centre variational approach to continuum orbitals in a B-spline basis, recently proposed for the H-2+ molecule, is improved by exploiting peculiar properties of the B-spline. A 'variable size basis', with less than half of the original number of functions, assures high accuracy in the H-2+ problem, in which the one-centre expansion is pushed to L(max) = 50. For the determination of HeH2+ phaseshifts, cross sections and asymmetry parameters up to 36 angular momentum components are coupled with the new approach.