Yasuo Kaneda

Analysis of valence XPS of (CH2CHR)n (R = H, CH3, OH and F), (CH2CH2NH)n and (CH2CH2O)n polymers by the semiempirical HAM/3 MO method using the n-mer (n = 2, 3, 4, 5) model

Abstract The valence X-ray photoelectron spectra (XPS) of six representative polymers [CH 2 CHR) n (RH, CH 3 , OH, F), (CH 2 CH 2 NH) n and (CH 2 CH 2 O) n ] were analysed by a semi empirical HAM/3 MO method using model molecules [H(CH 2 CHR) n H, (RH, CH 3 , OH, F), H 2 N(CH 2 CH 2 NH) n H, and HO(CH 2 CH 2 O) n H] with n = 2 to 5. The calculated AlK α photo electron spectra were obtained using Gaussian functions of an approximate linewidth (0.10 I k ); I k = I ′ k − WD , where I ′ k is the vertical ionization potential (VIP) of each MO and WD is a shift to account for sample work function, polarization energy and other effects. To explain the broader linewidth for the inner valence spectra, we propose that the lifetime of the 2s hole states are shorter because the holes can be filled by 2p electrons in ultra-violet emission or radiationless transition. The theoretical spectra showed good agreement with the observed spectra of the polymers between 0–40 eV. The present results suggest that the spectra can be analysed by the calculations for model trimers.