S. Shimada

Theoretical X-ray photoelectron and emission spectra of Si- and S-containing polymers by density-functional theory calculations using model molecules

Abstract The X-ray photoelectron and emission spectra (XPS and XES) of Si- and S-containing polymers [(–Si{–CH 2 –} 3 ) n (PCS), (–Si(CH 3 )(OH)–O–) n (PMHSO), (–Si(C 6 H 5 )(OH)–O–) n (PTES), (–Si(C 6 H 5 )(OH)–O–Si(CH 3 )(OH)–O–) n (PPMHSO), (–C 6 H 4 –O–C 6 H 4 –SO 2 –) n (PES)] were simulated by the deMon density-functional theory (DFT) calculations using the model molecules. The theoretical valence photoelectron and C Kα X-ray emission spectra showed good accordance with some experimental ones. The combined analysis of the valence XPS and C and O Kα XES enables us to divide the observed valence electronic distribution into the individual contributions for pσ-, pπ- and non-bonding MOs of the polymers.

Polymer conversion into amorphous ceramics by ion irradiation

We present results of X-ray fluorescence measurements (carbon Kα and Si L2,3) of methylhydroxylsiloxane and phenylmethylhydroxylsiloxane films. The films are converted into amorphous ceramics by irradiation with 500 keV C and 3 MeV Au ions. Changes in the composition (O/Si ratio) of some polysiloxane films are found when treated with ion irradiation. It is shown that ion irradiation induces a segregation of carbon atoms from methyl groups into diamond-like clusters whereas carbon atoms from phenyl groups maintain their sp2 configuration.