PHOTOIONIZATION OF BA+ IONS DUE TO CREATION OF 4D HOLE STATES

Photoion spectrometry has been applied to determine the relative photo ionization yields of Ba+ ions around the 4d ionization threshold. A gr ound state Ba+ ion beam was merged with monochromatized synchrotron ra diation over a length of 15 cm. Counting the number of doubly and trip ly charged ions produced in the interaction region, we have obtained p artial photoion yields as a function of photon energy. Prominent peaks due to resonance Auger processes have been observed below the thresho ld. A giant resonance structure above 4d threshold was seen only for t he Ba3+ spectrum.