Double Rydberg states of high angular momentum (l=6–8) produced in Ar viii byAr9+-Cs collisions

Abstract
Doubly excited states have been produced in Ar v i i i by double electron capture from cesium atoms by 90-keV Ar9+ ions. The transitions between 1s22s22p55g7l (l=3,...,6) 1s22s22p55g8l (l=4,...,7), and 1s22s22p55g9l (l=5,...,8) double Rydberg states have been observed by photon decays. The spectra have been analyzed using an independent-particle framework with a frozen-core approximation leading to a good agreement for transition energies.