The oscillator strength, f, of the1A1–1T2(t1–2e) transition of both chromate and permanganate ions have been calculated by LCAO-MO method using Slater type orbitals1(STO's) and by crystal field approach2. These computed values do not agree with the observed ones3. A detailed study of dipole moment of permanganate ion reveals4that STO's do not represent true state of affairs and more exact atomic orbitals must be used. The double-ζ 3d AO's with radial functions of the formwherederived by Richardson and hi8 coworkers5duplicate verg nearly the SCF AO's determined by Watson6, which are quite exact. ALCAO-MO paremetric calculation In terms of single parameter, β, the ligand mixing coefficient using Richardson's orbitals and both dipole velocity and dipole length operators has been reported in the present paper.