The charge exchange IVQ strength and the role of nonlocality forces

We evaluate commutators involving a general hamiltonian H and one body hermitian operators in the TDHF-RPA scheme and give explicit forms for such commutators in the case of schematic forces of separable type. The suggestion that nonlocal forces could be responsible for shifting the IVQ strength in the charge exchange channels and thus explain the nonobservation of this strength is investigated and found to be unjustified. In particular, we show that the relations used in that approach do not take into consideration the proper symmetry character of the interaction and lead to a breakdown of the sum rules. We then present the corrected relations for hamiltonians involving separable forces of mixed type and refer to an alternative explanation of the problem regarding the IVQ strength. (orig.)