Strong relativistic effect on (quasi)resonance electron-capture processes in non-symmetrical heavy ion-atom collisions

Abstract

(Quasi)resonance electron-capture processes in non-symmetrical $(Z_{\mathrm{P}}\simeq 2Z_{\mathrm{T}})$ heavy ion-atom collisions are studied employing a semiclassical atomic Dirac-Fock-Sturm orbital coupled-channel approach within an independent-particle model. %A special attention has been paid to study a role of the relativistic effects. Systematic calculations of the electron-capture cross sections of the target $K$-shell electrons to the $L$ subshells of the projectile have been carried out for the collisions of bare thorium $(Z_{\mathrm{P}}=90)$ and zinc $(Z_{\mathrm{P}}=30)$ nuclei with hydrogenlike ions $(Z_{\mathrm{T}}=36$-$47)$ and $(Z_{\mathrm{T}}=12$-$15)$, correspondingly. Strong relativistic effects, crucial for the case of Th${}^{90+}$-Ru${}^{43+}(1s)$ collisions in the low-energy regime, are found. Various one- and two-electron capture processes occurring in course of the collisions of the two-electron system Th${}^{90+}$-Ru${}^{42+}(1s^2)$ have been investigated in details in the wide range of collision energies $0.5$-$50$~MeV/u. The impact parameter dependencies of the double electron-capture processes are also presented. Our study demonstrates a very significant role of the relativistic effects for the processes, which becomes crucial in the low-energy regime.

26 pages, 17 figures