DETERMINATION OF DIPOLE POLARIZABILITIES FOR MG-MOMENT CANCELLATIONS(AND CA+ IONS FROM PRECISION LIFETIME MEASUREMENTS AND TRANSITION)

It is shown that precision lifetime measurements now available for the ns-np resonance transitions in alkali-metal-like atoms and ions and t he existence of strong cancellation effects in ns-n'p transitions for n'>n can be combined and used to specify the electric dipole polarizab ilities alpha(d) of these systems to a precision comparable to that of the Lifetime measurements. The method is described and applied to Mg and Ca+ ions. Existing precision lifetime measurements are coupled wi th Coulomb approximation with Hartree-Slater core calculations, which estimate the contribution of the n'>n transitions in near cancellation , and the analysis yields to values alpha(d)(Mg+)=(34.62+/-0.26)a(0)(3 ) and alpha(d)(Ca+)=(70.89+/-0.15)a(0)(3).