Nuclear structure near $N=108$ deformed shell gap: case of $^{187}$Os

International audienceOsmium nuclei lie between the axially deformed prolate rare earth [1] and spherical Pb nuclei [2]. Many of the even–even Os isotopes are known to be -soft and odd-A Os isotopes show rotational bands based on different multiquasiparticle configurations. The study of the dependence of different properties of these bands, e.g. the signature splitting, band crossing frequency, gain in alignment, etc., as a function of neutron and/or proton Fermi level is an important aspect in nuclear structure physics. The neutron Fermi levels in light Os nuclei lie in the mid-upper part of the i13/2 orbital, so their shapes tend to take appreciable prolate deformation. However, as the Fermi level moves up to the upper part of the i13/2 orbital, the oblate deformations are expected for the heavier ones. But the experimental data for heavier odd A Os isotopes are very scarce. We have performed an experiment to study the high spin state of 187Os and have extended its earlier established level scheme through the observation of several new bands and band crossings for the first time. The band built on 7/2- [503] configuration and its band crossing phenomenon have been discussed here