ORBITAL M1 VERSUS E2 STRENGTH IN DEFORMED-NUCLEI - A NEW ENERGY WEIGHTED SUM-RULE

Within the unified model of Bohr and Mottelson we derive the following linear energy weighted sum rule for low-energy orbital 1+ excitations in even-even deformed nuclei S(LE)lew(M1orb) congruent-to (6/5)epsilon[B(E2;0(1)+ --> 2(1)+K=0)/Ze2[r2]2]mu(N)2 with B(E2) the E2 strength for the transition from the ground state to the first excited state in the ground-state rotational band, [r2] the charge rms radius squared, and epsilon the binding energy per nucleon in the nuclear ground state. It is shown that this energy weighted sum rule is in good agreement with available experimental data. The sum rule is derived using a simple ansatz for the intrinsic ground-state wave function that predicts also high-energy 1+ strength at 2hwBAR carrying 50% of the total m1 moment of the orbital M1 operator.