ANALYSIS OF THE VALENCE X-RAY PHOTOELECTRON-SPECTRA OF 8 (-CH2-CHR-)(N) AND 2 (-CH2-C(CH3)R-)(N) POLYMERS BY THE SEMIEMPIRICAL HAM 3 MO METHOD USING THE TRIMER MODEL MOLECULES H-(-CH2-CHR-)(3)-H AND H-(-CH2-C(CH3)R-)(3)-H/

The valence X-ray photoelectron spectra of ten polymers [(-CH2-CHR-)(n ) (R=C6H5, OCH3, COCH3, COOH, COOCH3, OCQCH(3), CONH2, C4H6NO (N-vinyl pyrrolidone)) and (-CH2-C(CH3)R-)(n) (R=COOCH3 and CONH2)] were analyz ed by a semi-empirical HAM/3 MO method using trimer model molecules [H -(-CH2-CHR-)(3)-H (R=C6H5, OCH3, COCH3, COOH, COOCH3, OCOCH3, CONH2, a nd C4H6NO (N-vinylpyrrolidone) and H-(-CH2-C(CH3)R-)(3)-H (R=COOCH3 an d CONH2)], respectively. The calculated AlK alpha photoelectron spectr a were obtained using Gaussian functions of a fixed approximate linewi dth (0.10 I-k; I-k=I-k-Delta W, where I-k(,) is the vertical ionizatio n potential of each MO and Delta W is an approximate shift to account for the work-function effects. We assumed that Delta W corresponds to the shift that we must apply before we could compare the calculated sp ectrum for a single model molecule with the observed spectrum for the solid. The theoretical spectra showed good agreement with the spectra of the polymers, as observed between 0-40 eV.