Eur. Phys. J. A (2005) 25: 151-153
https://doi.org/10.1140/epjad/i2005-06-194-9

ENAM 2004

Study of the N = 77 odd- Z isotones near the proton-drip line

¹ Department of Physics and Astronomy, University of Tennessee, 37996, Knoxville, TN, USA
² Physics Division, Oak Ridge National Laboratory, 37831, Oak Ridge, TN, USA
³ Joint Institute for Heavy Ion Research, 37831, Oak Ridge, TN, USA
⁴ Department of Physics and Astronomy, Vanderbilt University, 37235, Nashville, TN, USA
⁵ H. Niewodniczański Institute of Nuclear Physics, PL-31342, Kraków, Poland
⁶ Oak Ridge Associated Universities, 37831, Oak Ridge, TN, USA
⁷ Department of Physics and Astronomy, Louisiana State University, 70803, Baton Rouge, LA, USA
⁸ Department of Physics and Astronomy, Mississippi State University, 39762, Mississippi State, MS, USA

^* e-mail: mtantawy@utk.edu

Received: 14 January 2005
Accepted: 27 April 2005
Published online: 11 August 2005

Abstract

The evolution of the πh _11/2νh _11/2 and πh _11/2νs _1/2 isomeric configurations was studied for the N = 77 isotones near the proton drip line. The decays of metastable levels in ¹⁴⁰Eu, ¹⁴²Tb , and ¹⁴⁴Ho were measured by means of X-, gamma- and conversion electron spectroscopy at the Recoil Mass Spectrometer at Oak Ridge. The sequence of isomeric levels in ¹⁴⁰Eu was experimentally determined. The half-life of the πh _11/2νh _11/2 state in ¹⁴²Tb was remeasured to be 25(1) μs. The spins and parities of 5^- and 8⁺ for the πh _11/2νs _1/2 and πh _11/2νh _11/2 ¹⁴²Tb isomers, respectively, were established from measured multipolarities. No evidence for the expected 1⁺ ground state was found in the ¹⁴⁴Ho decay data.