Molecular orbital calculations have been performed on a complex of chromium with iVjiV’-diphenyl-pyromellitimide, a compound structurally similar to the PMDA part of the PMDA-ODA polyimide repeat unit. The PMDA/Cr complex investigated involving chromium located above the central benzene ring is one of several possible complexes formed under the experimental conditions of clean surfaces and ultrahigh vacuum. The calculated C Is core levels, together with Koopmans’ approximation, provide a reasonable fit to the carbon is XPS data, if it is assumed that the observed spectrum reflects a portion of both reacted and unreacted molecular soecies. © 1987, American Chemical Society. All rights reserved.