Nuclear Data Sheets for A=149*1

Abstract

Nuclear spectroscopic information for known nuclides of mass number 149 (Cs,Ba,La,Ce,Pr,Nd,Pm,Sm,Eu, Gd,Tb,Dy,Ho,Er,Tm,Yb) with Z=55 to 70 and N=94 to 79 have been evaluated and presented together with adopted energies and Jπof levels in these nuclei. No excited state data are yet available for 149Cs, 149Ba, 149La, 149Tm and 149Yb. The existence of 149Cs is reported from mass separation of products from U(p,X) reaction and that of 149Yb from proton decays of 150Lu g.s. and 150Lu isomer. There are no half-life data for 149Cs and 149Yb. In 149Gd, 12 excited superdeformed bands have been reported, in addition to the yrast (g.s.) superdeformed band. In 149Tb, five superdeformed bands are known, whereas in 149Dy there is some evidence of superdeformation, but no discrete gamma rays have been found. The half-life of fully-ionized 149Dy isomer at 2661 keV has been reported to be 11 s, as compared to 0.49 s for the neutral atom. This evaluation supersedes previous full evaluations of A=149 by Nucl. Data Sheets 46 (1985) 1 and Nucl. Data Sheets 19 (1976) 337 and a midstream (in update mode) evaluation by Nucl. Data Sheets 73 (1994) 351