ACCURATE DENSITY-FUNCTIONAL CALCULATION OF CORE-ELECTRON BINDING-ENERGIES WITH A SCALED POLARIZED TRIPLE-ZETA BASIS-SET .3. EXTENSION TO OPEN-SHELL MOLECULES

Density functional theory and the unrestricted generalized transition state (uGTS) model were applied to study the core-electron binding ene rgies (CEBEs) of open-shell molecules. Basis set scaling based on Clem enti and Raimondi's rules for atomic screening was used along with the cc-pVTZ basis set. The scaled pVTZ basis set is almost as good as the cc-pV5Z and complete basis set limit in predicting CEBEs. For small m olecules (O-2, NO, NF2 and NO2) the average absolute deviation (aad) o f our prediction (scaled pVTZ) is only 0.29 eV. For the larger molecul e (CF3)(2)NO the aad is 0.56 eV, compared with experimental uncertaint y of 0.5 eV. Theoretical predicted multiplet splittings for the small molecules agree quite well with experiment: the average deviation is - 0.33 eV. For (CF3)(2)NO the calculated multiplet splittings are much s maller than the experimental ones. We also predict the CEBEs of PO, SN and SO, which have not been observed experimentally. (C) 1997 Elsevie r Science B.V.