ANALYSIS OF X-RAY PHOTOELECTRON-SPECTRA OF 8 POLYMERS BY DEMON DENSITY-FUNCTIONAL CALCULATIONS USING THE MODEL OLIGOMERS

The X-ray photoelectron spectra of eight polymers [(CH2CH2)(n), (CH2CH 2NH)(n), (CH2O)(n), (CH2CH2S)(n), (CH(2)CHX)(n), and (CH(2)CX(2))(n) ( X = F, Cl)] were analyzed by the deMon density-functional method using the model oligomers. Calculated AIK a valence photoelectron spectra w ere obtained using Gaussian line shape functions of an approximate Lin e width (0.10I(k)), where I-k = I-k' - WD, I-k' is the vertical ioniza tion potential of each MO, and WD is a shift to account for sample wor k function, polarization energy, and other effects. The theoretical sp ectra showed good agreement with the experimental spectra of the polym ers between 0 and 40 eV. The core-electron binding energies (CEBEs) of C1s, N1s, O1s, F1s, S2p, and Cl2p of the model oligomers were calcula ted by unrestricted generalized transition-state models. The differenc e between the calculated and the experimental CEBEs reflects the trend in WDs of the polymers.