Surface Flows of Soft Monopole Modes of 40Mg

In order to explore the nature of collective modes in weakly bound nuclei, we have investigated surface flow patterns of isoscalar monopole modes in a shape-coexisting nucleus 40Mg. The calculations were done in a fully self-consistent continuum finite-amplitude-method quasiparticle-random-phase-approximation (FAM-QRPA) in a large deformed spatial mesh. Our results demonstrated that the transition current densities at surfaces are nontrivial and dependent on deformations. The toroidal mode is favorable in the oblate shape, demonstrating the geometric deformation effects on nuclear surface flows. The surface flow patterns become more complicated as excitation energies increase. peerReviewed