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.
Instituut voor Kern- en Stralingsfysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
I
I
Stefanescu
G
G
Georgiev
D L
DL
Balabanski
N
N
Blasi
A
A
Blazhev
N
N
Bree
J
J
Cederkäll
T E
TE
Cocolios
T
T
Davinson
J
J
Diriken
J
J
Eberth
A
A
Ekström
D
D
Fedorov
V N
VN
Fedosseev
L M
LM
Fraile
S
S
Franchoo
K
K
Gladnishki
M
M
Huyse
O
O
Ivanov
V
V
Ivanov
J
J
Iwanicki
J
J
Jolie
T
T
Konstantinopoulos
Th
T
Kröll
R
R
Krücken
U
U
Köster
A
A
Lagoyannis
G
G
Lo Bianco
P
P
Maierbeck
B A
BA
Marsh
P
P
Napiorkowski
N
N
Patronis
D
D
Pauwels
G
G
Rainovski
P
P
Reiter
K
K
Riisager
M
M
Seliverstov
G
G
Sletten
J
J
Van de Walle
P
P
Van Duppen
D
D
Voulot
N
N
Warr
F
F
Wenander
K
K
Wrzosek