Inner electron excitation of iodine in the gaseous and solid phase

Abstract

The absorption spectra of gaseous and solid iodine have been measured in the photon energy range of 45–160 eV. The radiation of the 7.5 GeV electron synchrotron DESY was used as the light source. The intensity distribution of the $\text{4d→ ε f}$ continuum is discussed. A fine structure, similar in both phases, is found near the low‐energy side of this continuum. This fine structure can be ascribed to transitions of 4d_5/2 and 4d_3/2 electrons into the lowest empty molecular orbital and into Rydberg states of the molecule. One‐electron level energies and the 4d_3/2, 4d_5/2 ionization energies (58.95, 57.25 eV±0.2 eV) are deduced from the observed spectra. A rediscussion of the optical spectrum of the iodine molecule is given in the light of these results.