Photoionization of Ba⁺ions due to creation of 4d hole states

Abstract

Photoion spectrometry has been applied to determine the relative photoionization yields of Ba+ ions around the 4d ionization threshold. A ground state Ba+ ion beam was merged with monochromatized synchrotron radiation over a length of 15 cm. Counting the number of doubly and triply charged ions produced in the interaction region, we have obtained partial photoion yields as a function of photon energy. Prominent peaks due to resonance Auger processes have been observed below the threshold. A giant resonance structure above 4d threshold was seen only for the Ba3+ spectrum.