Corresponding Author

G.S.M. Ahmed

Authors ORCID


Document Type

Original Article

Subject Areas



Collective rotational model; Energy Staggering; Signature partner; Identical Bands; Superdeformed Nuclei


A total of eleven superdeformed rotational bands (SDRB’s) in the A=190 mass zone were described in the framework of a novel proposed simple phenomenological rotational formula as outcome of collective model. The proposed model contains the original pure rotation limit AI (I+1) plus perturbation term proportionate to the cubic power of the spin I. The bandhead spins and the model parameters were selected by a best fit method, utilizing a computerized search program to obtain best match between experimental and calculated transition energies. The spin propositions are mostly consistent with the findings of earlier works. The calculated gamma-ray transition energies (Eγ) over spin (EGOS) in all SDRB’s agree well with experimental data. Detailed assessment of the dynamic moments of inertia with rotational frequency is surveyed in details which proves to be quite helpful for understanding the SDRB’s properties such as identical bands (IB’s). Four pairs namely: 191Hg (SD2, SD3), 193Hg(SD3, SD4),194Hg(SD2, SD3) and 193Pb(SD3, SD4) are investigated as signature partners which exhibit △I=1 staggering effects their transition energies. We looked at this staggering by taking into account parameters that describe the variance between average transitions I+2 → I → I-2 and the I+1 → I-1 energies in its signature partner and a staggering parameter depends on the dipole transition energies connecting the two signature partners with that quadrupole transition energies. Large amplitude staggering is found. The bandhead moments of inertia of each signature partner pairs are found to be identical. Our calculations predicts the occurrence of △I = 2 staggering effects in 194Hg (SD1, SD2, SD3). This predict △I = 2 energy staggering has been inspected by computing parameter indicate the finite difference approximation to the fourth order derivative of that indicating energies. The phenomenon of IB’s is investigated for the nuclei 191Hg and 192Hg and their neighbors.

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