F. G. Kondev

Observation of γ vibrations and alignments built on non-ground-state configurations in Dy156

The exact nature of the lowest Kπ=2+ rotational bands in all deformed nuclei remains obscure. Traditionally they are assumed to be collective vibrations of the nuclear shape in the γ degree of freedom perpendicular to the nuclear symmetry axis. Very few such γ bands have been traced past the usual backbending rotational alignments of high-j nucleons. We have investigated the structure of positive-parity bands in the N=90 nucleus Dy156, using the Nd148(C12,4n)Dy156 reaction at 65 MeV, observing the resulting γ-ray transitions with the Gammasphere array. The even- and odd-spin members of the Kπ=2+γ band are observed up to 32+ and 31+, respectively. This rotational band faithfully tracks the ground-state configuration to the highest spins. The members of a possible γ vibration built on the aligned yrast S band are observed up to spins 28+ and 27+. An even-spin positive-parity band, observed up to spin 24+, is a candidate for an aligned S band built on the seniority-zero configuration of the 0+2 state at 676 keV. The crossing of this band with the 0+2 band is at ℏωc=0.28(1)MeV and is consistent with the configuration of the 0+2 band not producing any blocking of the monopole pairing.

Rotational band structures in N = 89 153 Gd

The reactions

Differential quadrupole moment measurements of the 1/2{sup +}[660] (i{sub 13/2}) neutron intruder band in {sup 133}Nd and {sup 135}Nd

{}^{152}\mathrm{Sm}(\ensuremath{\alpha},3n)

Exploring the I = 50-60 hbar domain: collective and terminating structures in 156Dy, 159Er and 160Er

at 37 MeV and

γ -soft Ba 146 and the role of nonaxial shapes at N≈90

{}^{124}\mathrm{Sn}{(}^{36}\mathrm{S},\ensuremath{\alpha}3n)

High-resolution α and electron spectroscopy of Cf 98 249

at 165 MeV were used to produce high-spin states in the transitional rare-earth nucleus

M-3 and E-4 K-forbidden decays of the Kpi=23/2- isomer in Lu-177

{}^{153}\mathrm{Gd}.

High-spin yrast structure of 159Ho

Significant extensions in angular momentum and excitation energy with respect to earlier work were achieved and several new rotational sequences were observed. The rotational behavior of

Heavy rotation – evolution of quadrupole collectivity centred at the neutron-rich doubly mid-shell nucleus 170Dy

{}^{153}\mathrm{Gd}

Single-particle and collective excitations in Ni62

is described in terms of quasiparticle assignments and the observed alignment properties are analyzed within the framework of the cranked shell model. Detailed comparisons with other