Significance of the compound nucleus surface energy coefficients in the synthesis of the superheavy nuclei with $\textbf{Z=112-120}$

Abstract

This paper investigates the impacts of the different surface energy coefficients on the compound nucleus decay modes during heavy ion fusion reactions, with focus given to the superheavy nuclei (SHN) in the range of $Z=112-118$. The evaporation-residue (ER) cross sections were calculated for different surface asymmetric constants, $k_{s}$ and surface energy constants, $\gamma_{0}$. In these calculations, the di-nuclear system model and proximity potential, along with considering deformed nuclei, were employed. Comparing the experimental data and this theoretical approach, the best values of $k_{s}$ and $\gamma_{0}$ are $0.7546$ and $0.9180~\mathrm{MeV~fm^{-2}}$, respectively. Furthermore, this new model was used to investigate the probability of synthesis of experimentally unknown heavier systems with $Z=119$ and $120$. There exist five promising combinations to synthesize SHN with $Z=119$: a) ${^{249}}\mathrm{Cf}({^{45}}\mathrm{Sc},3n){^{291}}119$, b) ${^{249}}\mathrm{Cf}({^{45}}\mathrm{Sc},4n){^{290}}119$, c) ${^{247}}\mathrm {Bk}({^{50}}\mathrm{Ti},3n){^{294}}119$, d) ${^{254}}\mathrm{Es}({^{48}}\mathrm{Ca},3n){^{299}}119$, and e) ${^{254}}\mathrm{Es}({^{48}}\mathrm{Ca},4n){^{298}}119$. In addition, it is found that the best combinations to synthesize SHN with $Z=120$ are ${^{249}}\mathrm{Cf}({^{50}}\mathrm{Ti},3n){^{296}}120$, and ${^{251}}\mathrm{Cf}({^{50}}\mathrm{Ti},3n){^{298}}120$.