Investigating fusion–fission and quasifission in reaction populating 188Pt compound nucleus

Fission dynamics of 188 Pt, a neutron deficient nucleus in newly discovered mass asymmetric sub-Pb region, have been explored via fission fragments mass-angle and mass-total kinetic energy distributions, at energies around and above the barrier. The observed correlations of fragment mass and emission angle indicate the presence of fission events originating from a non-equilibrated source. Mass-total kinetic energy spectra are relatively broader and the dependence of measured mean total-kinetic-energy on fragment mass is also broader than the expected parabolic dependence for liquid drop fission behaviour, at all studied energies. The measured mean total kinetic energy values are higher than the prediction of Viola systematics. The widths of measured total kinetic energy distributions are also inconsistent with the observed systematic behaviour of compound nucleus (CN) in this mass region. These observation of mass-angle and mass-total kinetic energy distributions revealed the clear signatures of the presence of slow quasifission in the fission of 188 Pt compound nucleus. These findings indicate the role of entrance channel parameters such as mass asymmetry and charge product Z P Z T in Fusion-Fission and quasi-fission dynamics. Dynamical model calculations do not predict the presence of quasi-fission for the present reaction system.