Test of a q-fractional V(N-q) Hartree-Fock potential for the calculation of double photoionization cross sections of neon

The approach of a parametric V(N-q) Hartree-Fock potential with fractional q is developed and applied for the first time for the calculation of the do uble photoionization cross sections of Ne. A minimum of the squared differe nce between the length-form and velocity-form cross sections is used as a c riterion for calculating the values of q. It is found that the minimization procedure leads to a practically exact equality of the length-form and vel ocity-form cross sections for the Ne III 2s(2)2p(4)[P-3, D-1, S-1], 2s(1)2p (5)[P-3, P-1] and 2s(0)2p(6)[S-1] states in the exciting-photon energy regi on from the double-ionization threshold up to 325 eV, if q is considered as a function of the exciting-photon energy. The calculated V (N-q) cross sec tions are in better agreement with the experimental data than those for the V ((N-1)) and V ((N-2)) potentials.