Coulomb excitation of 172Yb

Abstract

The nucleus 172Yb has been Coulomb excited using beams of 16O, 32S and 58Ni. The transitional and diagonal E2 matrix elements of the ground band have been measured up to spin 14 + and 12 +, respectively, as well as the transitional E2 matrix elements between the lowest-lying levels of both the K π = 0 + band at 1043 keV and the K π = 2 + band at 1466 keV and the ground band. The data are compared with the predictions of simple geometric collective models and with the IBA-1 model. The K π = 2 + band is likely to be the γ-band, and the experimental data are well reproduced by both the asymmetric rotor model with an asymmetry parameter of γ ⋍ 5°, and by the rotation-vibration model. The K π = 0 + excited band is found to be strongly deformed, but the excitation of the band is non-collective, which cannot be reproduced by any of the models.