AUTOIONIZATION RESONANCES IN ATOMIC CHLORINE

The ejected electron spectra from keV collisions between Cl atoms and inert gases have been studied as a function of the impact energy in th e 2-60 keV range. The energy spectra of 5-20 eV electrons exhibit two types of autoionizing Cl resonances, (i) at low impact energies with t he 3s3p(5)nl configuration, (ii) at higher energies with the 3s(2)3p(3 )nln'l' configuration. Due to spin selection in the collisions, the 3s (2)3p(3)(D-2) core resonances are expected to be predominantly populat ed, with nln'l' being 4s(2) and 3d4s, but parent mixing between (S-4) and (D-2) cores invalidates this simple description. The angular distr ibutions of electrons ejected from some of the collisionally excited C l resonances have been measured to test the proposed assignments. The population of the 3s3p(5)nl and 3s(2)3p(3)nln'l' resonances contribute s significantly to the ionization yield in Cl-He, -Ne collisions.