Electric-dipole transitions in 165 Er *

Abstract High-spin states of 165 Er were studied using the 160 Gd( 9 Be, 4n)reaction at beam energies of 42and 45 MeV. The previously known bands based on the 5/2 [523] and 5/2 + [642] con gurations have beenextended to high-spin states. Electric-dipole transitions linking these two opposite parity bands were observed.Relatively large B(E1) values have been extracted experimentally and were attributed to octupole softness.Key words fusion-evaporation reaction, high-spin state, electric-dipole transition, octupole softnessPACS 21.10.Re, 23.20.Lv, 27.70.+q 1 Introduction Generally, low-energy electric-dipole (E1) transi-tions observed in nuclei are strongly hindered andthe major part of the E1 transitions is shifted tothe giant dipole resonance (GDR) of energy higherthan 10 MeV [1|3] . The low-energy B(E1) valueswith single-particle estimation are typically 10 6 inWeisskopf units. In some cases, E1 transitions ob-served between two rotational bands with oppositeparity are enhanced as compared to single-particleexpectations