XPS study of the electronic structure of the diamagnetic p-nitroaniline molecule and the 4,4,5,5-tetramethyl-2-phenyl-4,5-dihydro-1H-imidasol-3-oxide-1-oxyl nitroxide radical

Abstract

Interpretation of X-ray photoelectron spectra (XPS) for p-nitroaniline and the nitroxide radical was carried out by the time-dependent density functional theory (TD-DFT) method using the (Z+1)N–1 approximation. Consideration of satellite transitions in the interpretation of the XPS spectra leads to good agreement with experiment. The shape of the X-ray photoelectron spectra of the radicals mainly depends on the relaxation processes caused by the X-ray hole screening effect and leading to the formation of satellite lines. The structure of the satellites in the XPS spectra depends on the spin state of the system and intermolecular interaction.