The capture of many electrons by Ar !7+ ions, at low velocity, near a metallic surface, has been studied. Multiexcited bound states with many electrons in the outermost shells (hollow atoms) have been observed. The surrounding of an ionic excited core by many outermost electrons greatly decreases the lifetimes of the states. This characteristic decrease explains the main striking features of the relaxation of the ions.

Excited levels were attributed to 81 31 Ga50 for the first time which were fed in the β-decay of its mother nucleus 81 Zn produced in the fission of nat U using the ISOL technique. We show that the structure of this nucleus is consistent with that of the less exotic proton-deficient N = 50 isotones within the assumption of strong proton Z = 28 and neutron N = 50 effective shell effects.

No abstract