Auger decay of Na-likeSi3+(2p53lnl’) states formed in slowSi5+→He and Ar ion-atom collisions

High-resolution autoionization spectra of multiply charged Na-like states in silicon are presented. These states have been populated in collisions of Si{sup 5+} ions with 50 keV impact energy on two gas targets: He and Ar. The electron emission following the decay of core-excited 2{ital p}{sup 5}3{ital lnl}{prime} ({ital n}=3--6) levels in Si IV has been measured. The comparison of electron spectra obtained after collisions with He and Ar is given. Theoretical Auger energies due to core-excited (2{ital p}{sup 5}3{ital s}{sup 2}), (2{ital p}{sup 5}3{ital s}3{ital p}), (2{ital p}{sup 5}3{ital p}3{ital d}), (2{ital p}{sup 5}3{ital s}4{ital s}), and (2{ital p}{sup 5}3{ital s}4{ital f}) states have been calculated relative to the (2{ital p}{sup 6}){sup 1}{ital S} limit by using the multiconfiguration Hartree-Fock method. Additional theoretical estimates of Auger transition energies originating from (2{ital p}{sup 5}3{ital p}{sup 2}), (2{ital p}{sup 5}3{ital d}{sup 2}), (2{ital p}{sup 5}3{ital s}4{ital d}), (2{ital p}{sup 5}3{ital s}5{ital p}), (2{ital p}{sup 5}3{ital s}6{ital s}), (2{ital p}{sup 5}3{ital s}6{ital p}), and (2{ital p}{sup 5}3{ital s}6{ital g}) are also presented.