Vorticity of threshold strength in neutron drip-line nuclei.

By adopting a finite square-well potential, the analytic expressions of vorticity strengths, which are related to transverse currents, are derived for some selected E1 and E2 transitions. From these analytic expressions it can be seen clearly that, like the threshold strengths, the vorticity strengths are also sharply distributed just above the threshold in nuclei near the drip-line and mainly come from the orbits with small binding energy. [ABSTRACT FROM AUTHOR]