Analysis of C1s Spectra of N-, O-, and X-Containing Polymers in X-Ray Photoelectron Spectroscopy by ab initio Molecular Orbital Calculations Using Model Molecules

Abstract

C1s X-ray photoelectron spectra of ten polymers [(CH2-CH2-NH)n, (CH2-CHR)n (R=CN, CONH2, F, OCOCF3, COOCH2CF3, Cl), (CH2(CH2)3CH2-CONH)n, (CH2-CX2)n (X=F, Cl)] were simulated from Koopmans’ theorem by an ab initio molecular orbital (MO) calculations of HONDO7 program using the model molecules. The theoretical spectra showed fairly good accordance with the experimental spectra, although we used the energy shifted value and the linewidth of a Gaussian lineshape function for each core C1s MO value as 21.0 eV and 1.3 eV, respectively. The core-electron binding energies (CEBEs) of C1s for model molecules of polymers [(CH2-CH2-NH)n, (CH2-CHR)n (R=CN, F, Cl), (CH2-CX2)n (X=F, Cl)] were calculated by deMon density functional theory program with scaled polarized valence triple-zeta (scaled-pVTZ) basis set. The WD (sum of work funktion and other energy effects) of the polymers was evaluated as 5.2–6.4 eV from the difference between the calculated CEBEs of the model molecules and the experimental CEBEs of the polymers.