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

Analysis of Valence XPS of Hydrocarbon Polymers Modified by He-Ion Bombardment

“…This quantity WD denotes the sum of the work function of the sample and other energy effects, as stated in our previous studies. [12][13][14] For ionization of an electron from molecular orbital (MO) φ k , for example, we can apply the Janak theorem. 20 For the VIPs of the valence regions, we use the so-called diffuse ionization (DI) model which Asbrink et al 21 proposed in the HAM/3 method.…”

“…25 In the case of the linewidth (WH(k)), we used WH(k) = 0.10 I k for the models, as adopted in previous works. [12][13][14] …”

“…The line width of each peak of ionization energy I k was taken to be 0.10 I k (proportional to the ionization energy) as stated in previous works. [12][13][14] In the present work, we perform surface analysis of hydrocarbon polymers (polyethylene (PE), polypropylene (PP), polystyrene (PS)) by He-ion bombardment from the theoretical and experimental valence X-Ray photoelectron spectra (XPS). In the case of He ionbombardment, He ions are light elements, compared with carbon, which is the main component of the polymers, and it would be expected that energy loss of injected He-ions to polymers is due only to inelastic collision.…”

“…ory (DFT) program 10 which uses the idea of transitionstate, 11 Endo and co-workers [12][13][14][15][16][17][18] performed excellent assignments of XPS of seventy polymers by the DFT calculations using model oligomers, because they used the energy shift WD (work function (W) and other energies (delta, D)) [12][13][14][15][16][17][18] to account for solid-state effects. The simulation of the valence spectra was performed on the model molecules using standard convolution by each Gaussian line shape and using the Gelius intensity model 19 for molecular photo-ionization cross-sections.…”

Toward a computational and experimental model of a poly-epoxy surface

“…polymers, is a challenge but it is established that experimental spectra are directly related to the electronic states obtained from calculations on smaller model molecules. For instance, Endo et al presented a comprehensive analysis of the XPS C 1s spectra for polymers using the negative of the energy of molecular orbitals [19,20]. More recently, they used the 'transition state' theory [21] for the calculation of the core electron binding energies [22,23].…”