Wang Dianxun

A study of the surface of carbon fiber by means of X-ray photoelectron spectroscopy. III

Abstract This paper reports a study of the surface composition of carbon fibers treated by various methods by means of X-ray photoelectron spectroscopy (SPS). C 1 S X-ray photoelectron spectra showed that after the surface treatment of carbon fibers, the carbon atoms in the hydrocarbon were changed into etc. oxygen-containing groups, that is, the results of surface oxidation and concentration increased with time but finally reached a constant level. Comparing experimental results for the treatments used, we found that all of these methods resulted in concentrations of oxygen groups on the surface in the order: . Evidence was found for the formation of lactone groups during treatment in an oxygen or nitrogen plasma, but not during treatment by nitric acid or anodic oxidation.

He I photoelectron spectroscopic studies of the electronic structure in some forked conjugated systems. Experimental and theoretical studies of the molecular orbital character of the compounds

Abstract The He I photoelectron spectra of thienyl polyenic phenyl ketones and phenyl polyenic thienyl ketones have been studied. To assign these spectra MNDO molecular orbital calculations for the named molecules have also been carried out. The results show that, (a) the reduction of HOMO ionization potentials in the same series of compounds is directly proportional to the number of ethylenic groups in the molecules; (b) the polyenic group conjugates only with the conjoint thienyl ring in the thienyl polyenic phenyl ketones, but in the phenyl polyenic thienyl ketones the polyenic group conjugates only with the conjoint phenyl ring, i.e. the carbonyl group can be considered as an obstructing group for complete molecular conjugation and so there is no conjugated π bond system of the whole molecule; (c) in the compounds the contributions of the atoms from the thienyl ring and from the thienyl ethylenic group to their respective HOMO are large, i.e. the conjugated competitions of the thienyl ring and of the thienyl ethylenic group are stronger than those of the phenyl ring and of phenyl ethylenic group in the respective molecules of these two compounds; (d) there is a conjugated π bond through the conmplete molecule in the compound

Electronic structure and conformation properties of halogen-substituted acetyl acrylic anhydrides, CX3C(O)OC(O)CH═CH2 (X = H, F, or Cl).

Acetyl acrylic anhydride (CH(3)C(O)OC(O)CHCH(2)) and its halogen-substituted derivatives (CF(3)C(O)OC(O)CHCH(2) and CCl(3)C(O)OC(O)CHCH(2)) were prepared by the heterogeneous reaction of gaseous CH(2)═CHC(O)Cl with CX(3)C(O)OAg (X = H, F, or Cl). The molecular conformations and electronic structure of these three compounds were investigated by HeI photoelectron spectroscopy, photoionization mass spectroscopy, FT-IR, and theoretical calculations. They were theoretically predicted to prefer the [ss-c] conformation, with each C═O bond syn with respect to the opposite O-C bond and the C═C bond in cis orientation to the adjacent C═O bond. The experimental first vertical ionization potential for CH(3)C(O)OC(O)CHCH(2), CF(3)C(O)OC(O)CHCH(2), and CCl(3)C(O)OC(O)CHCH(2) was determined to be 10.91, 11.42, and 11.07 eV, respectively. In this study, the rule of the conformation properties of anhydride XC(O)OC(O)Y was improved by analyzing the different conformations of anhydrides with various substitutes.