Single ionization of the 11Se and 21Po states of He by 1-GeV/u U92+ ions

We report calculations of the cross sections for single ionization of the ground $1{}^{1}S$ and excited $2{}^{1}P$ helium states by relativistic impact of a bare uranium ion of charge ${Z}_{p}=92$ with energy 1 GeV/u. The heavy particle collision is treated within the semirelativistic first Born approximation. The nonrelativistic initial and final two-electron correlated atomic states are obtained by numerical procedures from variational principles. The continuum final states are considered below the $n=2$ threshold of the ${\mathrm{He}}^{+}$ ion. The differential ionization cross section $d\ensuremath{\sigma}/dE$ is obtained for electron energies $E<~37\mathrm{eV}.$ This energy range includes a wide nonresonant region as well as the resonance structures due to the autoionizing helium states ${(2s}^{2}){}^{1}S,$ $(2s2p){}^{1}P$ and ${(2p}^{2}){}^{1}D.$