Two-electron wavefunctions for the ground state of alkali negative ions

Analytic wavefunctions are proposed to determine the energy of the ground s tate of all alkali negative ions. These functions fulfil the cusp condition s at the singularities of the Coulombic field, and include the correct beha viour for large interparticle separations, They should be useful to determi ne cross sections of inelastic processes involving two-electron systems as well as to treat interactions between ionic and covalent states in long-ran ge-type models of alkali dimers.