Probing onset of nuclear vaporization in heavy ion collisions

Abstract

The onset of nuclear vaporization in heavy-ion collisions is examined in the present study. For this, we perform Quantum Molecular Dynamics (QMD) model calculations supplemented with clusterisation algorithm for fragment identification, namely Simulated Annealing Clusterization Algorithm (SACA) approach. Our results with much sophisticated SACA method show a nice agreement with experimental findings of vaporization (predicted by asymptotic behaviour of average fragment charge) in $^{16}$\textrm{O} $+$ $^{80}$\textrm{Br} and $^{16}$\textrm{O} $+$ $^{10 7}$\textrm{Ag} collisions. Further, we predicted the energy of onset of vaporization for $^{40}$\textrm{Ca} $+$ $^{40}$\textrm{Ca}, $^{84}$\textrm{Kr} $+$ $^{84}$\textrm{Kr}, $^{132}$\textrm{Xe} $+$ $^{132}$\textrm{Xe} and $^{197}$\textrm{Au} $+$ $^{197}$\textrm{Au} collisions by investigating gas/liquid content and probability of vaporization (and it's derivative) \emph{vs} incident energy behaviour. These two observables probe the critical point of nuclear vaporization in much sophisticated manner, relative to average fragment charge. Our findings on these two novel variables to predict the energy of onset of vaporization are verifiable in experiments. The influence of colliding geometry as well as role of the Coulomb interactions is also studied to understand the system size effects on the nuclear vaporization.