Absolute photoionization cross section from the 6s6p 1,3P1 excited states of barium

Abstract

We present photoionization cross section measurements from the 6s6p 1P1 and 3P1 excited states of barium at and above the first ionization threshold. The experiments have been performed using a thermionic diode ion detector in a space charge limited mode in conjunction with a Nd:YAG laser system and the saturation technique to determine the photoionization cross sections. The absolute values of the photoionization cross section from the 6s6p 1P1 and 3P1 excited states at the first ionization threshold have been determined as 90 ± 14 Mb and 102 ± 15 Mb, respectively. The measured values of the photoionization cross section from the 6s6p 1P1 excited state are compared with available experimental and theoretical work, while the absolute photoionization cross sections from the 6s6p 3P1 excited state are reported for the first time.