Absolute photoionization cross sections of I+ and I2+ in the 4d ionizationregion - art. no. 020702

The absolute photoionization cross sections of I+ and I2+ ions have been me asured from 45 to 140 eV, covering the region of 4d ionization where a larg e maximum, also known as a "giant resonance," occurs in the cross section. For both ions, the maximum cross section appears near 90 eV and is measured to be 23(3) Mb and 24(4) Mb, respectively. This is significantly larger th an that previously reported for atomic iodine, and only slightly smaller th an the values calculated using the random-phase approximation with exchange .