General properties of the pi h(9/2)[541]1/2(-) configuration and level scheme of Tm-165

Jensen, HJ Bark, RA Tjom, PO Hagemann, GB Bearden, IG Carlsson, H Leoni, S Lonnroth, T Reviol, W Riedinger, LL Schnack-Petersen, H Shizuma, T Wang, XZ Wrzesinski, J

Hj. Jensen et al., General properties of the pi h(9/2)[541]1/2(-) configuration and level scheme of Tm-165, NUCL PHYS A, 695, 2001, pp. 3-50

110

INGLESE

Review

Physics

NUCLEAR PHYSICS A

0375-9474 → ACNP

695

2001

3 - 50

ISI

0375-9474(200112)695:<3:GPOTPH>2.0.ZU;2-B

Tm-165 has been studied through the reactions Nd-150(F-19,4n), E-beam = 85 MeV and Sm-154 (N-15, 4n), E-beam = 70 MeV. The level scheme has been exten ded to spin 71/2(-)h, and four new bands have been added. Two are assigned to the K = 17/2, three-quasiparticle configurations, pi [523]7/2(-) x nu [6 42]5/2(+) x nu [523]5/2(-) and pi [404]7/2(+) x nu [642]5/2(+) x nu [523]5/ 2(-), and the remaining two are assigned to gamma -vibrations coupled to an h(9/2) proton. Lifetimes of high-spin states in the [541]1/2(-) and [411]1 /2(+) bands have been measured using DSAM techniques, allowing transition q uadrupole moments to be deduced. Furthermore, crossings between the [541]1/ 2(-) and [523]7/2(-) bands and between the [411]1/2(+) and [404]7/2(+) band s are analysed with a band-mixing calculation to obtain the quadrupole mome nts of the [523]7/2(-) and [404]7/2(+) bands. While the [523]7/2(-), [411]1 /2(+) and [404]7/2(+) bands all have similar deformations, the [541]1/2(-) band has a quadrupole moment approximately 15% larger. The relative deforma tions are in good agreement with diabatic potential energy surface calculat ions performed using the code "Ultimate Cranker". The experimental crossing frequency, due to the alignment Of i(13/2) neutrons, is found to be delaye d in the [541]1/2(-) band compared to the other bands. This is a universal feature in the rare-earth region, and extensive systematic Cranked Shell Mo del calculations have been performed to predict deformations and crossing f requencies for nuclei in the region. The model is unable to reproduce the f ull delay in crossing frequency, confirming that deformation alone is not r esponsible for the shift. (C) 2001 Elsevier Science BX All rights reserved.