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An excited state of 12 C having excitation energy (E x ) 9.65 ± 0.02 MeV and width (FWHM) 607 ± 55 keV, which decays to three α particles via Hoyle state (E x = 7.65 MeV), has been directly identified in the exclusive inelastic scattering of 60 MeV 4 He on 12 C, measured in coincidence with the recoiling 12 C Hoyle state (decaying mostly as 12 C* → 8 Be gs → α → α + α + α) by event-by-event kinematic reconstruction of the completely detected (4α) events. This state is likely to be a candidate for 2 2 + first excited of Hoyle state.

Fission fragment mass distribution has been measured in two reactions to populate compound nu- cleus 246 Bk. Both the target nuclei were deformed. However, entrance channel mass asymmetry of the two sys- tems was on the either side of the Businaro Gallone mass asymmetry parameter. Near the Coulomb barrier, at similar excitation energies, the width of the fission fragment mass distribution was found to be significantly dif- ferent for the 14 N + 232 T h reaction compared to the 11 B + 235 U reaction. The entrance channel mass asymmetry was found to play a significant role in deciding the fusion process.

Using the major accelerator facilities available in India, detailed experimental studies have been made to understand the mechanism of quasi-fission and role of nuclear shell effect in heavy nuclei. Fission fragment mass distribution has been used as the probe to explore the role of entrance channel effects on fusion-fission and quasi- fission dynamics. Fission fragment mass distribution has also been demonstrated to be useful to identify the phenomenon of 'washing out' of nuclear shell effect with excitation energy.

The quantitative contributions of various direct three alpha decay mechanisms in the decay of the famous Hoyle state, the 02 + resonant excited state of 12 C at excitation energy of 7.65 MeV, has been estimated using 60 MeV α inelastic scattering on 12 C target in complete kinematical measurement. Simultaneous optimisation of three different distributions (the relative energy of 8 Be like pairs, the root mean square energy deviation and the radial projection of symmetric Dalitz plot) derived from the experimental data with those generated from the Monte Carlo simulated event sets, have been done to arrive at a consistent estimation of the contributions of various direct decay modes.