T. Koizumi et al., PHOTOIONIZATION OF BA+ IONS DUE TO CREATION OF 4D HOLE STATES, Journal of physics. B, Atomic molecular and optical physics, 28(4), 1995, pp. 609-616
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.