الفهرس 
ِAcknowledgementOnly 14 pages are availabe for public view
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Abstract
By using a computer simulated search program, the experimental dynamical moment of inertia values were fitted with Harris three parameter - expansion formula in terms of even powers of the rotational frequency. The best expansion parameters obtained from the fit were used to assign the spins of the bandheads of rotational bands in thirteen doubly even superdeformed nuclei in the mass regions A ~ 150 and A ~ 190 by integrating the calculated dynamical moment of inertia. The intrinsic alignment angular momentum was assumed to be zero. The values of the spins resulting from this approach are excellent consistent with all spin assignments of other approaches. The studied superdeformed nuclei are: iSD- 1, SD-3 of Gadolinium 148 (148Gd), SD-1 of Gadolinium 150 (150Gd), SD-1 of Dysprosium 152 (152DY), SD-1 of Mercury 190(190Hg), SD-1 of Mercury 192 (192Hg), SD-1, SD-2a, SD-2b of Mercury 194(,94Hg), SD-1 ■ Lead 192(192Pb), SD-lof Lead 194 (l94Pb), SD-1 of Lead 196 (196Pb) Lid SD-1 of Lead 198 (l98Pb).
The perturbed SU(3) limit of the sdg interacting boson model is applied to describe the spectroscopy of the superdeformed nuclear rotational bands. A four parameter simple analytic formula for the eigenvalue equation was used. The g bosons were taken into account and *e SUSdg(3) symmetry was perturbed by introducing an interaction fWding the SOSdg(5) symmetry. The optimized model parameters for each ■Kleus have been adjusted by fitting procedure. The quality of energy its is measured by the standard energy root mean square deviation.
The E2 transition y - ray energies, rotational frequencies and ■ynamical moments of inertia have been calculated and examined for the Selected superdeformed nuclei which show no evidence of either irregular behavior near the bottom of the bands or abrupt angular momentum alignment at low rotational frequency. For A ~ 150 region, however, the amical moment of inertia mostly decreases with increasing rotational frequency but with a great deal of variation from nucleus to nucleus, ^cording to the number of occupied intruder orbitals. For A ~ 190 region fccept at high frequencies most of the superdeformed bands have namely the same dynamical moment of inertia with typically increase smoothly as rotational frequency increases. This behavior has been attributed ■airily to the successive gradual alignment of quasiparticle pairs Occupying specific high -N intruder orbitals originating from the i13a tproton and j 15/2 neutron orbitals in the presence of weak pair correlations.
In our analysis we found that, the differences in y - ray energies l/VEy between transitions in the two yrast superdeformed bands of the (isotones 192Hg(l)and 194Pb(l) were small and constant up to rotational frequency hw ~ 0.25MeV. Therefore, these two bands have been iponsidered as identical bands. This behavior was also studied in terms of the dynamical moment of inertia J <2), it was found that the J (2) values (were identical. Above hw ~ 0.25MeV, the J (2) moment of inertia of the Pb(l) band becomes smaller than that of 192Hg(l), indicating the appearance of a plateau at higher frequency. The behavior of J (2) was plainly due to the disappearance of pairing correlations.
The similarities in dynamical moments of inertia in the Mercury |Hg) isotopes and Lead (Pb) isotopes were be demonstrated in a plot of their incremental alignment as a function of rotational frequency, each ■dative to the yrast band in1 2Hg nucleus. A constant incremental alignment of zero indicates a pair of identical bands
The E2 transition y - ray energies, rotational frequencies and ■ynamical moments of inertia have been calculated and examined for the Selected superdeformed nuclei which show no evidence of either irregular behavior near the bottom of the bands or abrupt angular momentum alignment at low rotational frequency. For A ~ 150 region, however, the amical moment of inertia mostly decreases with increasing rotational frequency but with a great deal of variation from nucleus to nucleus, ^cording to the number of occupied intruder orbitals. For A ~ 190 region fccept at high frequencies most of the superdeformed bands have namely the same dynamical moment of inertia with typically increase smoothly as rotational frequency increases. This behavior has been attributed ■airily to the successive gradual alignment of quasiparticle pairs Occupying specific high -N intruder orbitals originating from the i13a tproton and j 15/2 neutron orbitals in the presence of weak pair correlations.
In our analysis we found that, the differences in y - ray energies l/VEy between transitions in the two yrast superdeformed bands of the (isotones 192Hg(l)and 194Pb(l) were small and constant up to rotational frequency hw ~ 0.25MeV. Therefore, these two bands have been iponsidered as identical bands. This behavior was also studied in terms of the dynamical moment of inertia J <2), it was found that the J (2) values (were identical. Above hw ~ 0.25MeV, the J (2) moment of inertia of the Pb(l) band becomes smaller than that of 192Hg(l), indicating the appearance of a plateau at higher frequency. The behavior of J (2) was plainly due to the disappearance of pairing correlations.
The similarities in dynamical moments of inertia in the Mercury |Hg) isotopes and Lead (Pb) isotopes were be demonstrated in a plot of their incremental alignment as a function of rotational frequency, each ■dative to the yrast band in1 2Hg nucleus. A constant incremental alignment of zero indicates a pair of identical bands.