Highly anomalous yrast B(E2) values and vibrational collectivity

Abstract

It is shown that the existing yrast B(E2) values [especially the B(E2;4(1)(+)-->2(1)(+))/B(E2;2(1)(+)-->0(1)(+)) ratio] in Ru-98 are highly anomalous and cannot be plausibly interpreted with existing models. A survey of all even-even nuclei from 40less than or equal toZless than or equal to80 shows that this phenomenon is rare in collective nuclei. It occurs to a much lesser extent in Te-114, Xe-114, and possibly a few other nuclides. The combination of vibrational-like energies and nonvibrational B(E2) values perhaps points to a different kind of vibrational behavior.