Interplay between single-particle and collective effects in the odd-A Cu isotopes beyond N=40.
Collective properties of the low-lying levels in the odd-A 67-73Cu were investigated by Coulomb excitation with radioactive beams. The beams were produced at ISOLDE and postaccelerated by REX-ISOLDE up to 2.99 MeV/u. In 67,69Cu, low-lying 1/2(-), 5/2(-), and 7/2(-) states were populated. In 71,73Cu, besides the known transitions deexciting the single-particle-like 5/2(-) and core-coupled 7/2(-) levels, gamma rays of 454 and 135 keV, respectively, were observed for the first time. Based on a reanalysis of beta-decay work and comparison with the systematics, a spin 1/2(-) is suggested for these excited states. Three B(E2) values were determined in each of the four isotopes. The results indicate a significant change in the structure of the odd-A Cu isotopes beyond N=40 where single-particle-like and collective levels are suggested to coexist at very low excitation energies.
Stefanescu
I
I
Instituut voor Kern- en Stralingsfysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
Georgiev
G
G
Balabanski
D L
DL
Blasi
N
N
Blazhev
A
A
Bree
N
N
Cederkäll
J
J
Cocolios
T E
TE
Davinson
T
T
Diriken
J
J
Eberth
J
J
Ekström
A
A
Fedorov
D
D
Fedosseev
V N
VN
Fraile
L M
LM
Franchoo
S
S
Gladnishki
K
K
Huyse
M
M
Ivanov
O
O
Ivanov
V
V
Iwanicki
J
J
Jolie
J
J
Konstantinopoulos
T
T
Kröll
Th
T
Krücken
R
R
Köster
U
U
Lagoyannis
A
A
Lo Bianco
G
G
Maierbeck
P
P
Marsh
B A
BA
Napiorkowski
P
P
Patronis
N
N
Pauwels
D
D
Rainovski
G
G
Reiter
P
P
Riisager
K
K
Seliverstov
M
M
Sletten
G
G
Van de Walle
J
J
Van Duppen
P
P
Voulot
D
D
Warr
N
N
Wenander
F
F
Wrzosek
K
K