EXCLUSION OF SPURIOUSITY THROUGH EFFECTIVE OPERATORS

The method of Liu and Zamick for the exclusion of spurious M1 strength through effective operators is extended to isoscalar and isovector op erators and applied to heavy deformed nuclei using a Woods-Saxon poten tial plus pairing. The isoscalar orbital, strength is almost purely sp urious and carries most of the total amount of spuriousity. The method gives the exact summed nonspurious strength,but becomes approximate w hen applied to single If excitations. The accuracy of this approximati on is:studied here by comparison with exact, rotationally invariant ra ndom-phase-approximation results. It is shown that for some residual i nteractions the ''approximate'' results can be very, different from th e exact ones even in the presence of relatively small changes in the B (M1) values or close to the exact results even for large changes. Exac t results are at present the only reliable test for the validity of ap proximate methods for the removal of spuriousity.