Bhoomika Maheshwari

Odd tensor electric transitions in high-spin Sn-isomers and generalized seniority

Abstract The similar behavior of the B ( E 1 ) values of the recently observed 13 − odd tensor E 1 isomers and the B ( E 2 ) values of the 10 + and 15 − even tensor E 2 isomers in the Sn-isotopes has been understood in terms of the generalized seniority for multi- j orbits by using the quasi-spin scheme. This simple approach proves to be quite successful in explaining the measured transition probabilities and the corresponding half-lives in the high-spin isomers of the semi-magic Sn-isotopes. Hence, we show for the first time the occurrence of seniority isomers in the 13 − Sn-isomers, which decay by odd-tensor E 1 transitions to the same seniority states.

Asymmetric behavior of the B(E2↑;0+ → 2+) values in 104–130Sn and generalized seniority

Abstract We present freshly evaluated B ( E 2 ↑ ; 0 + → 2 + ) values across the even–even Sn-isotopes which confirm the presence of an asymmetric behavior as well as a dip in the middle of the full valence space. We explain these features by using the concept of generalized seniority. The dip in the B ( E 2 ) values near 116 Sn is understood in terms of a change in the dominant orbits before and after the mid shell, which also explains the presence of asymmetric peaks in the B ( E 2 ) values. This approach helps in deciding the most active valence spaces for a given set of isotopes, and single out the most useful truncation scheme for Large Scale Shell Model (LSSM) calculations. The LSSM calculations so guided by generalized seniority are also able to reproduce the experimental data on B ( E 2 ) ↑ values quite well.

Conservation of Isospin in Neutron-Rich Fission Fragments

Abstract On the occasion of the 75 t h anniversary of the fission phenomenon, we present a surprisingly simple result which highlights the important role of isospin and its conservation in neutron rich fission fragments. We have analysed the fission fragment mass distribution from two recent heavyion reactions 238U(18O,f) and 208Pb(18O,f) as well as a thermal neutron fission reaction 245Cm( n t h ,f). We find that the conservation of the total isospin explains the overall trend in the observed relative yields of fragment masses in each fission pair partition. The isospin values involved are very large making the effect dramatic. The findings open the way for more precise calculations of fission fragment distributions in heavy nuclei and may have far reaching consequences for the drip line nuclei, HI fusion reactions, and calculation of decay heat in the fission phenomenon.

Role of isospin and its conservation in neutron-rich fission fragments

Following upon our earlier paper [1] containing some initial results, we present detailed discussion and complete results in this paper, which provide the first direct evidence for the validity of isospin as a nearly good quantum number in neutron-rich systems. The evidence comes from the reproduction of the general features of the partition-wise relative yields of neutron-rich fission fragments produced in two heavy-ion induced fusion fission reactions, namely

g-factor calculations from the generalized seniority approach

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Atlas of Nuclear Isomers

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6 + isomers in neutron-rich Sn-isotopes beyond N= 82 and effective interaction

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Generalized seniority states and isomers in tin isotopes

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Role of neutrons in the coexistence of magnetic and antimagnetic rotation bands in 107 Cd

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Generalized Seniority Schmidt Model and the g-factors in Semi-magic Nuclei.

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