Near-Threshold Resonance Enhancement of Neon Valence Satellites Studied with Synchrotron Radiation

Abstract
Photoelectron spectra of the neon valence satellites have been measured in their near-threshold region. Strong resonance enhancement of the satellite cross section is observed as a result of autoionization of doubly excited Rydberg states. The nonresonant cross section of most satellites follows approximately that of the 2p main line as close as 0.5 eV above threshold. The resonant behavior is explained with respect to correlation effects showing the importance of interchannel coupling for the satellite production. The characteristic differences in the satellite threshold behavior are used to distinguish between relaxation effects and other electron correlations.