TWO-PHOTON DETACHMENT FROM HALOGEN NEGATIVE IONS G.F.Gribakin, V.K.Ivanov, A.V.Korol and M.Yu.Kuchiev University of New South Wales, Sydney, Australia; St.Petersburg State Technical University, ST.Petersburg, Russia; Russian Maritime Technical University, St.Petersburg, Russia Two-photon detachment cross sections and photoelectron angular distributions for halogen negative ions are calculated within the lowest order of perturbation theory. The calculations are performed both within the Hartree-Fock approximation and within the method combining the corrected ground state and the Hartree-Fock excited state wavefunctions. We show that imposing a correct asymptotic behaviour of the ground state wavefunction has a significant effect on the cross section values.