Effect of initial-state geometric configurations on the nuclear liquid-gas phase transition
Yixing Cao, Xian-Gai Deng, Y. G.
Abstract
Within the framework of an extended quantum molecular dynamics model, we simulated $^{40}\mathrm{Ca}+^{16}\mathrm{O}$ collisions at beam energies ranging from 60 to 150 MeV/nucleon for $^{16}\mathrm{O}$ with different $\ensuremath{\alpha}$-cluster configurations. Results imply that different $\ensuremath{\alpha}$-cluster configurations lead to different yields of deuteron, triton, $^{3}\mathrm{He}$, and $^{4}\mathrm{He}$, but not for proton and neutron. We discuss the effect of geometric fluctuations which are presented by double ratios of light nuclei, namely ${\mathcal{O}}_{\text{p-d-t}}$ and ${\mathcal{O}}_{\text{p-d-He}}$. It is found that the magnitude hierarchy of geometric fluctuations is chain, kite, square, and tetrahedron structures of $^{16}\mathrm{O}$. ${\mathcal{O}}_{\text{p-d-t}}$ has maximum value around 80--100 MeV/nucleon, which could be related to liquid-gas phase transition, that is consistent with results from the charge distribution of the heaviest fragments in the collisions.