New isomer in ⁹⁶Y marking the onset of deformation at N = 57

Author： Iskra Ł. W. Fornal B. Leoni S. Bocchi G. Petrovici A. Porzio C. Blanc A. De France G. Jentschel M. Köster U. Mutti P. Régis J.-M. Simpson G. Soldner T. Ur C. A. Urban W. Bazzacco D. Benzoni G. Bottoni S. Bruce A. Cieplicka-Oryńczak N. Crespi F. C. L. Fraile L. M. Korten W. Kröll T. Lalkovski S. Márginean N. Michelagnoli C. Melon B. Mengoni D. Million B. Nannini A. Napoli D. Podolyák Zs. Regan P. H. Szpak B.

Publisher： Edp Sciences

E-ISSN： 1286-4854|117|1|12001-12001

ISSN： 0295-5075

Source： EPL (EUROPHYSICS LETTERS), Vol.117, Iss.1, 2017-03, pp. : 12001-12001

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

The level scheme of ⁹⁶Y was significantly extended and a new 201 ns isomer was located at 1655 keV excitation energy, with spin-parity assignment of 5^± or 6⁻. The isomer decays to spherical low-spin structure by transitions with large hindrance and is fed by a short cascade which resembles the beginning of a rotational band. This is in analogy with the feeding and decay pattern of the 4⁻ isomer in ⁹⁸Y, here confirmed, by lifetime analysis, as a bandhead of a rotational structure with sizable deformation. It is suggested that the new isomer in ⁹⁶Y arises from a shape change between deformed and spherical configurations, which indicates the appearance of deformation already at N = 57 in the yttrium chain. The experimental findings for ⁹⁶Y are strengthened by theoretical calculations based on the complex Excited Vampir model.