Density-functional calculation of the inner-shell spectra for two stable enol tautomers: acetylacetone and malonaldehyde

In this paper we report results from our theoretical studies on two P-diketones which exist as stable enol tautomers: acetylacetone and malonaldehyde. We found that density functional theory (DFT) with Becke's exchange functional and Perdew's correlation functional can accurately predict the core-electron binding energies (CEBEs) of both molecules. The oxygen 1s --> pi* inner-shell excitation spectra (ISES) of both tautomers have also been studied using our DFT procedure. The CEBEs for the corresponding carbons and oxygens of the C=O and C-OH groups of malonaldehyde are larger than those of acetylacetone, The first term values corresponding to a core-hole on the carbonyl oxygen were found to be larger than those with a core-hole on the enol oxygen. The observation indicates that the effect of a core-hole in the proximity of pi*: orbital has a stronger effect on increasing the electron affinity of the core-ionized cation. (C) 1998 Elsevier Science B.V. All rights reserved.