105Tc nuclear structure and systematic evolution of states of 1/2+[431] intruder band in odd-A 95,97,99,101,103,105,107Tc isotopes

Abstract

Previously observed negative and positive parity states of 105Tc were studied in the framework of the particle-rotor model. Transition properties and experimental energies were compared to the predictions of model calculations. A systematic study of the evolution of the intruder π1/2+[413] band in the nuclear structure of odd-A technetium isotopes 95,97,99,101,103,105,107Tc is presented as well. The existence of this intruder band has been argued previously in 95,97,99,101,103Tc isotopes (partially populated) and fully observed and confirmed in 105Tc. It will be shown that changes in deformation and subsequently the position of the Fermi level, vis a vis the 1/2+[431] intruder orbital originating from the π(d5/2, g7/2) subshells, predominantly affect these systematic changes. All four interpreted experimental rotational bands are naturally predicted by the rotational model as bands build on states of good Ω originating from the 5/2+[422], 5/2–[303], 3/2–[301], and 1/2+[431] orbitals near the Fermi level in deformed 105Tc (strong coupling). Further experimental investigation about missing data are needed for those observed in low lying states in both 105Tc and 103Tc to confirm the presence of the 1/2–[301] rotational band that is well defined in lighter 95,97,99,101Tc isotopes.