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With the aim of investigating the influence of fragment nuclear structure e.g. shell closure configuration and odd-even nature on the scission configuration, fragment angular momenta have been deduced from the radiochemically determined independent isomeric yield ratios of the fission products ltlPd, 131Te, 133Te, 134I and 13SCs in 252Cf spontaneous fission. The fragments' angular momenta deduced are 8.8_+1.5, 5.8 _+ 1.0, 6.1 _+ 1.1, 11.5 _+ 1.1 and 9.8 __ 1.2h respectively. The angular momenta data from this work and literature have been analysed to arrive at fragments' deformations at the scission bringing out the influence of the spherical 82n and deformed 66n and 88n shells. The fragment angular momenta were also seen to be inversely correlated to their elemental yields exhibiting odd-even fluctuations. This has been explained in terms of equilibration of the collective degrees of freedom in low energy fission.

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In the present work the influence of initial excitation energy and angular momentum of the fissioning system on the angular momenta of fission fragments corresponding to ' 'Te and ' Te was studied in the Th(a3OM, v, f) system. The fragment angular momenta were estimated from the radiochemically determined independent isomeric yield ratios using a statistical model. The obtained data are discussed along with the literature data on the fragment angular momenta in the same fissioning nucleus 23 U formed in the U(n, h, f) and " Th(a, f}systems.NUCLEAR REACTIONS~~Th(a3O M v f) reaction, fragment angular momentum, independent isomeric yield ratio, initial excitation energy, angular momentum, single particle effect.

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In the present work angular momenta of the fragments corresponding to 132Im'g have been deduced from the radiochemically determined independent isomeric yield ratios and statistical model based analysis in neutron induced fission of 235U, 239pu and 245Cm and spontaneous fission of 252Cf. These data along with similar data on 134I, reported earlier from this laboratory, bring out the effects of deformed 66n and spherical 82n shells on fragment angular momentum showing also an inverse correlation of the latter with elemental yields. Quantitative estimates of fragment scission point deformation and the coefficient of change of fragment angular momentum with kinetic/excitation energy have been deduced and are seen to be in good agreement with the expected theoretical estimates.

In this paper we have studied the two-pion exchange three-nucleon potential (2πE−3NP ) using an approximate SU (2) × SU (2) chiral symmetry of the strong interaction. The off-shell pion-nucleon scattering amplitudes obtained from the Weinberg Lagrangian are supplemented with contributions from the well-known σ-term and the ∆(1232) exchange. It is the role of the ∆-resonance in 2πE − 3NP , which we have investigated in detail in the framework of the Lagrangian field theory. The ∆-contribution is quite appreciable and, more significantly, it is dependent on a parameter Z which is arbitrary but has the empirical bounds |Z| ≤ 1/2. We find that the ∆-contribution to the important parameters of the 2πE − 3NP depends on the choice of a value for Z, although the correction to the binding energy of triton is not expected to be very sensitive to the variation of Z within its bounds.

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