HIGH-RESOLUTION PROJECTILE AUGER-SPECTROSCOPY FOR LI, BE, B AND C EXCITED IN SINGLE GAS COLLISIONS .1. LINE ENERGIES FOR PROMPT DECAYS

The ejected-electron spectra of highly excited autoionising levels of Li, Be, B and C have been studied by using the projectile electron spectroscopy method. Singly and doubly core-excited states are strongly populated in 100 to 500 keV Li+, Be+, B+ and C+ single collisions with He and CH4. High resolution is obtained by selecting a small observation angle (6.4 degrees ) with respect to the beam axis. Numerous states, previously not seen, have been resolved and identified by comparison with existing theoretical data. For a large number of core-excited states, absolute Auger transition and excitation energies are given. In particular, isoelectronic sequences for singly core-excited lithium-like (Z=2-16) and doubly core-excited helium-like (Z=1-14) autoionising states are studied.