Comparative study of octupole excitations on superdeformed states in 32S, 36S, 40Ca and 50S

By means of an RPA calculation based on the deformed Woods-Saxon potential in the coordinate-mesh representation, we make a comparative study of octupole excitations built on superdeformed states in the 40Ca region and those in 50S. For the N=Z stable nuclei, 32S and 40Ca, enhancement of octupole transition strengths results from the coherence of the proton and neutron excitations. Contrastingly, for 50S close to the neutron drip line, we find that the low-lying state created by the excitation of a single neutron from a loosely bound low Ω state to a high Ω resonance state acquires an extremely large transition strength. A similar enhancement of the octupole strength is also found in oblately deformed 40Mg close to the neutron drip line. (author)