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Physical Review C, Nuclear Physics

Publication date: 2011-01-01
Volume: 83
Publisher: Published for the American Physical Society by the American Institute of Physics

Author:

Balabanski, DL
Ionescu-Bujor, M ; Iordachescu, A ; Bazzacco, D ; Brandolini, F ; Bucurescu, D ; Chmel, S ; Danchev, M ; De Poli, M ; Georgiev, G ; Haas, H ; Huebel, H ; Marginean, N ; Menegazzo, R ; Neyens, Gerda ; Pavan, P ; Alvarez, C Rossi ; Ur, CA ; Vyvey, Katrien ; Frauendorf, S

Keywords:

neutron-deficient pb, shears mechanism, magnetic rotational band, quadrupole moment, pb-193, Science & Technology, Physical Sciences, Physics, Nuclear, Physics, NEUTRON-DEFICIENT PB, SHEARS MECHANISM, DIPOLE BANDS, STATES, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, 5106 Nuclear and plasma physics

Abstract:

The spectroscopic quadrupole moment of the T-1/2 = 9.4(5) ns isomer in Pb-193 at an excitation energy E-ex = (2585 + x) keV is measured by the time-differential perturbed angular distribution method as vertical bar Q(s)vertical bar = 2.6(3) e b. Spin and parity I-pi = 27/2(-) are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the coupling of a neutron hole in the 1i(13/2) subshell with the (3s(1/2)(-2)1h(9/2)1i(13/2))(11-) proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation epsilon(2) = -0.11, similar to that of the 11(-)proton intruder states, which occur in the even-even Pb nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.