Band structures of121,123I

Abstract

The band structures of 121,1231 nuclei have been studied using a version of the particle-rotor-model in which the experimental excitation energies of the neighbouring (A-l) cores can be fed directly as input parameters. The calculations have been carried out with axially symmetric Nilsson potential with both prolate and oblate deformations. The parameters of the model have been chosen from earlier theoretical work and experimental odd-even mass differences. Only the Coriolis attenuation factor has been treated as adjustable parameter. The theoretical band structures are in very good agreement with the available experimental data.

Excited states in129I

“…A similar conclusion was reached for 123,125 I based on core-quasiparticle coupling model [36] or particle-rotor model (PRM) calculations [37], and for 127 I in the frame of the particle-triaxial-rotor model [38]. The three-particle cluster core coupling model investigation of Ref.…”

Particle-rotor-model calculations in 125I

“…The details of the PRM calculations are similar to those reported previously for ½¾½ ½¾¿ I [12]. The motion of the odd proton in deformed Nilsson orbit is coupled to the rotation of the core through the Coriolis interaction.…”

“…The identification of the 13/2 and 17/2 states in ½¾ I as members of the unfavoured sequence [2], based on their decay pattern, suggests that the ½½ ¾ band in ½¾ I may also have a structure similar to those in the lighter iodine nuclei, rather than a vibrational nature. Particle-rotor-model calculations have been previously used to understand the structure of the ½½ ¾ band in ½¾½ ½¾¿ I [12]. Accordingly, PRM calculations were performed for ½¾ I using both ½¾ Te and ½¾ Xe as the core.…”

High-spin states in127I

“…Thus, an alternative description was proposed for the two I = 2 bands; i.e., the two decoupled bands were interpreted as a I = 1 band based on the πd 5/2 /πg 7/2 mixed configuration. In addition, such coupled structures can be well reproduced with oblate deformations in 121,123,125 I [2,9,10], supporting such an alternative interpretation. energy of 32 MeV.…”

“…Theoretically, band structures in heavier odd-A 121-127 I can be well reproduced within the framework of the core-quasiparticle coupling model [2,9] and the particle-triaxial-rotor model, taking into account both prolate and oblate deformations [10,21]. These calculations also showed that the πd 5/2 , πg 7/2 , and high-πh 11 tion of β 2 ∼ −0.15 [10,[19][20][21]. In fact, the experimentally measured static quadrupole moments for the I π = 5/2 + and 7/2 + states in heavier odd-A 125−133 I have negative sign [22].…”