Eur. Phys. J. A (2005) 26: 265-269
https://doi.org/10.1140/epja/i2005-10172-5

Original Article

Characterization of quasiparticle states at and beyond stability in ytterbium isotopes: Spectroscopy of ¹⁷⁵Yb, ¹⁷⁶Yb and ¹⁷⁷Yb

¹ iThemba Laboratory for Accelerator Based Sciences, P.O. Box 722, 7129, Somerset West, South Africa
² Department of Physics, University of Stellenbosch, Private Bag X1, 7602, Matieland, South Africa
³ Department of Physics, University of Cape Town, Private Bag, 7701, Rondebosch, South Africa
⁴ Department of Physics, University of the Western Cape, Private Bag X17, 7535, Bellville, South Africa

^* e-mail: smm@tlabs.ac.za

Received: 25 July 2005
Accepted: 16 November 2005
Published online: 28 November 2005

Abstract

Excited states in ¹⁷⁵Yb, ¹⁷⁶Yb and ¹⁷⁷Yb were populated via the bombardment of a ¹⁷⁶Yb target with a 750 MeV ¹³⁶Xe beam. Gamma-ray decays from these states were measured with the AFRODITE multi-detector spectrometer. The rotational band previously assigned to the ground state of ¹⁷⁷Yb has been reassigned to the first-excited state of ¹⁷⁵Yb. A new rotational band based on the ground state of ¹⁷⁷Yb is presented, and the band based on the K ^π = 4^- two-quasiparticle state in ¹⁷⁶Yb has been identified. Also a candidate for the rotational band based on the K ^π = 8^-, T _1/2 = 11.4(3) s two-quasiparticle state in ¹⁷⁶Yb has been found. Comparisons of g_K values derived from in-band branching ratios are consistent with the ν9/2⁺[624] assignment to the ground state of ¹⁷⁷Yb, the ν²{9/2⁺[624] ⊗ 1/2^-[510]} assignment to the K ^π = 4^- state and with the ν²{9/2⁺[624] ⊗ 7/2^-[514]} assignment to the K ^π = 8^- metastable excited state in ¹⁷⁶Yb.