| In this work, near spherical nucleus112In was studied in A-110mass region. The experiment was performed through110Pd (7Li,5n)112In reaction with the beam provided by the HI-13tandem accelerator of CIAE in Beijing. The110Pd target with an enrichment of97.2%and a thickness of2.4mg/cm2was rolled onto an Au backing. The γ-ray detecting array consist of14HPGe detectors. Each detector is surrounded by BGO anti-Compton shield. The bombarding energy of50MeV was selected to populate the nucleus112In by the excitation function measurements. A total of1.9×108two fold coincidence events were collected. A symmetrized coincidence matrix and a nonsymmetrized Directional Correlation ratios of Oriented states (DCO) matrix were constructed for off-line analysis. These matrices were analyzed by using the RADWARE package. By analyzing the (γ-γ) coincidence relations and DCO ratios ofytransitions, the level scheme of112In has been established.Two new bands were found basing on the level scheme of112In established. Configuration assignments for each of the rotational bands were made based on the single particle Nilsson diagram, aligned angular momentum of quasi-particles, systematic comparison, and electromagnetic properties analysis.The shape of nuclei is almost spherical or only weakly deformed in A-80, A--110, A-140and A-190mass region. The magnetic dipole vector, which arise from proton particles (holes) and neutron holes (particles) in high-j orbits, rotates around the total angular momentum vector. At the band-head, the proton and neutron angular momentum are increased by an alignment of the proton and neutron angular momentum along the total angular momentum. Consequently, the orientation of the total angular momentum in the intrinsic frame does not changes so much and regular rotational bands are formed. An increase in the total angular momentum is generated by the simultaneous closing of these two blades along the direction of the angular momentum vector of aligned neutron particles. Hence, this band is called "shears band". There are two different kinds shears bands according to the micro-mechanism generate the total angular momentum. One is△1=1bands, where the proton and neutron spin vectors are approximately perpendicular to each other, summing to the total angular momentum. Another is△1=2bands, antimagnetic rotation, where a pair of proton holes are antiparallel at the bandhead, but gradually align along the axis.In experiment,195magnetic rotational bands in85nuclei were found since the discovery of the first magnetic rotational band in199Pb. For example,5SFe and60Ni in A-60mass region, Rb, Kr and Br isotopes in A-80mass region, Cd, In, Sn, Sb and Te isotopes in A-110mass region, Tb, Gd and Dy isotopes in A～140mass region, and so on. However, the data on antimagnetic rotational bands are rare. So far, antimagnetic rotational bands were found only in100Pd,144Dy,108,110In and Cd isotopes. In this text, systematic studies are performed on a magnetic rotational band and a candidate antimagnetic rotational band in112In.The tilted axis cranking calculations based on the sophisticated covariant density functional theory calculations, based on the configurationπg-29/2g7/2(?)Vh11/2before the alignment and πg-29/2g7/2(?)Vh311/2after the alignment, well reproduce the experimental results, which further support the configuration assignment.Moreover, the experimental angular momentum as a function of rotational frequency at the top and bottom of new band in112In and antimagnetic rotational (AMR) band in108110in are far smaller than that of the superdeformed band, and also smaller than the value for A=110rigid spherical rotor. This means that these bands are not based on a collective behavior. Therefore, the new band in112In is thought tentatively as AMR band, following the assignment for AMR band in110In. |
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