RESONANCE STRUCTURE AND ABSOLUTE CROSS-SECTIONS IN NEAR-THRESHOLD ELECTRON-IMPACT EXCITATION OF THE 4S(21)S-]4S4P(3)P INTERCOMBINATION TRANSITION IN KR6+

First measurements of absolute total cross sections for electron-impac t excitation of an intercombination transition to a nonradiating state of an ion are reported. The cross sections for near-threshold excitat ion of the 4s2 1S --> 4s4p 3p transition of Kr6+ are dominated by diel ectronic resonances. The measurements can serve as a benchmark for the oretical predictions of dielectronic resonance structure in the excita tion of multicharged ions.