Accurate variational determination of continuum wavefunctions by a one-centre expansion in a spline basis. An application to H+2and HeH2+photoionization

Abstract

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.