Neutron-Proton Interaction in Odd-Odd Deformed Nuclei

Calculations of the energy splittings between the parallel and antiparallel coupling states of odd neutron and odd proton in deformed nuclei have been made for both zero-range and finite-range nuclear forces. The energy splittings for both types of forces agree with the corresponding experimental energies. Calculations have also been made for the odd-even shift in $K=0\mathrm{}$ bands. Finite-range interactions improve the agreement between experiment and theory for the odd-even shift, but the results are still unsatisfactory. It is shown that a tensor force is important in reproducing the experimental odd-even shift, especially in the case where ${\Sigma }_n+{\Sigma }_p=1\mathrm{}$.