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A representation of the fusion barrier distributions has been deduced from the back angle quasielastic scattering cross section data in O-1618+ Sn-12,Sn-124 reactions, measured over a wide range of bombarding energies around the Coulomb barrier. The results have been compared with coupled channel calculations using the CCDEF code to study the effects of projectile and target inelastic excitations and nucleon transfer couplings on the representation of fusion barrier distributions in these systems. The present studies bring out the importance of coupling of 2n pickup in the O-16+ Sn-120,Sn-124 reactions and 2n stripping in the O-18+ Sn-120,Sn-124 reactions in explaining the observed barrier distributions.

Fission fragment angular distributions have been measured for B-10(spin=3(+)), B-11(spin=3/2(-))+Th-232 reactions at projectile energies below and above the Coulomb barrier. The fragment anisotropies for the B-11 +Th-232 system are found to be significantly larger than the statistical saddle point model (SSPM) predictions at sub-barrier energies, while for the B-10+Th-232 system the deviations from SSPM predictions are found to be much less. The present results indicate that the ground state spin of the projectile influences the fragment anisotropies at sub-barrier energies in a larger way than predicted by the statistical model with the inclusion of the M-state distributions. Calculations were carried out based on the entrance channel dependent K-states distribution and preequilibrium fission models, with inclusion of ground state spin of the projectiles, which are found to explain the variation of fission fragment anisotropies as a function of bombarding energy for both the systems.

Quasielastic (QE) and transfer excitation function measurements have been carried out for the O-16, F-19 + Th-232 systems at theta(lab) = 170 degrees over a wide energy range above and below the Coulomb barrier. The data were analyzed to obtain the representation of fusion barrier distributions as well as the mean square compound nuclear spin values ([l(2)]), which are found to compare well with the results of the standard fusion model (CCDEF) calculations. Further, the back-angle transfer cross-section data as a function of the bombarding energy were transformed to give the transfer probabilities as a function of the distance of closest approach for 1p, 2p, 1 alpha, and 1p1 alpha transfer channels. The experimental "slope parameters" derived from these data were compared with the predictions of the semiclassical model calculations. It is found that the results for single nucleon or single cluster transfers are well explained by the semiclassical model, whereas for multinucleon or cluster transfers, the calculations underpredict the transfer probabilities.