Theoretical X-ray photoelectron spectra of polymers by deMon DFT calculations using the model dimers

Otsuka, Takao; Endo, Kazunaka; Suhara, Michihiko; Chong, Delano P.

doi:10.1016/s0022-2860(99)00364-6

Cited by 32 publications

(17 citation statements)

References 46 publications

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“…The calculated CEBEs of model dimers for the six polymers using uGTS model in our previous work 16 showed well agreement in the average absolute deviation of 0.30 eV with the experimental CEBEs 34 of the similar chemical structural molecules in the gas phase. Then, we have proposed in previous works 10 -12, 14, 16 that the reliable WD value of the polymers can be estimated from the difference between the computed CEBEs of the model oligomers and the experimental values of the polymers.…”

Section: Xps Of Pe Pp Pvme and Pvmk Polymerssupporting

confidence: 75%

“…For the VIPs of the valence regions, we introduced the restricted generalized diffuse ionization (rGDI) model, 16 which is just the extension of the restricted diffuse ionization (rDI) model that Asbrink and coworkers proposed in the HAM/3 method. 20 In the rGDI model, as indicated in our previous work, 16 the 2/3 electron is removed evenly from all α and β valence MOs and the negative resulting orbital energies are approximated as each F (2/3) for each valence MO.…”

Section: Cebes Vips and Auger Electron Energiesmentioning

confidence: 99%

“…The line width of each peak of ionization energy I k was taken to be 0.08I k (proportional to the ionization energy) as stated in previous works. 16 In the present study, we perform theoretical assignments for XPS and AES of four polymers [(CH 2 CH 2 ) n (PE), (CH 2 CH (CH 3 )) n (PP), (CH 2 CH(OCH 3 )) n (PVME), (CH 2 CH(COCH 3 )) n (PVMK)] by DFT calculations. Our aim in this work is to establish a theoretical approach to analyses of experimental AES for the polymers from deMon-KS DFT calculations.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical auger electron spectra of polymers by density functional theory calculations using model dimers

et al. 2001

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We propose a new approach for analysis of Auger electron spectra (AES) of polymers by density functional theory (DFT) calculations with the Slater's transition-state concept. Simulated AES and X-ray photoelectron spectra (XPS) of four polymers [(CH2CH2)n (PE), (CH2CH(CH3))n (PP), (CH2CH(OCH3))n (PVME), and (CH2CH(COCH3))n (PVMK)] by DFT calculations using model dimers are in a good accordance with the experimental ones. The experimental AES of the polymers can be classified in each range of 1s-2p2p, 1s-2s2p, and 1s-2s2s transitions for C KVV and O KVV spectra, and in individual contributions of the functional groups from the theoretical analysis.

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Section: Xps Of Pe Pp Pvme and Pvmk Polymerssupporting

confidence: 75%

Section: Cebes Vips and Auger Electron Energiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Theoretical auger electron spectra of polymers by density functional theory calculations using model dimers

et al. 2001

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“…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]. Following this work and in a first approach, we compute the molecular orbitals energies on model molecules as preliminary input for the assignment of experimental XPS spectra of the investigated polymer.…”

Section: Introductionmentioning

confidence: 99%

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

Duguet

Bessaguet

Aufray

et al. 2015

Applied Surface Science

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a b s t r a c tA model poly-epoxy surface formed by the reaction of DGEBA and EDA is studied by the combination of experiments and DFT calculations. A special synthesis protocol is presented leading to the formation of a surface that is smooth (S a < 1 nm), chemically homogeneous, and that presents a low-defect density (0.21 m −2 ), as shown by AFM characterizations. Then, XPS is used for the determination of the elemental and functional groups' surface composition. DFT allows the identification and assignment of individual bonds contributions to the experimental 1s core-level peaks. Overall, we demonstrate that such a model sample is perfectly suitable for a use as a template for the study of poly-epoxy surface functionalization.

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“…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.…”

mentioning

confidence: 99%

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

Koizumi

Nakao

Endo

et al. 2001

Polym J

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ABSTRACT:Surface analysis of hydrocarbon polymers (polyethylene (PE), polypropylene (PP), polystyrene (PS)) by He-ion bombardment was performed from the theoretical and experimental valence X-Ray photoelectron spectra (XPS). The polymers were He-ion bombarded at an energy of 150 keV with fluences between 1 × 10 12 and 1 × 10 15 ions cm −2 . The bombardment destroys the chemical bonds of the polymer surface and activates carbon atoms near the surfaces.They may produce radicals and recombine with oxygen in the residual gas and/or atmospheric oxygen. We consider that experimental results for valence XPS of the polymers due to the bombardment are simulated by deMon density-functional theory (DFT) calculations using the model trimers, or dimer of neutral, radical, cationized, and oxidized compounds. KEY WORDS Valence X-Ray Photoelectron Spectra (Valence XPS) / He-Ion Beam / Polymers (polyethylene, polypropylene, polystyrene Polymers (PE, PP, PS)) / Density-Functional Theory Calculation (DFT Calculation) / Polymers are now used in widely many prototype applications such as material science in plastic moldings, sheets, fibers, and films, and in composites with inorganic materials, in protective coatings, sealants, and adhesives. In such applications, two groups of workers 1, 2 showed that ion bombardment is a useful method for modification of surface properties, such as wear resistance, corrosion resistance and bio-compatibility for polymers. Iwaki and co-workers 3-7 have demonstrated that ion implantation or bombardment is applied to the surface modification of polymers to improve blood and tissue compatibility. As a fundamental investigation, it is very important to provide information on the surface and chemical bonding properties of such polymers. Nakao et al. 8 investigated the chemical bonding states of carbon surface structure near the top surface of Ne ion-bombarded polystyrene and oxygen plasma-treated polystyrene by means of X-Ray photoelectron spectroscopy and surface-enhanced Raman spectroscopy to examine the cause of cell adhesion control on polymers. Recently, they 9 have analyzed the relationship between surface chemical bonding states and He-ion bombarded effects of polyethylene and polypropylene with X-Ray photoelectron spectroscopy measurements. We think most of the interesting chemistry and physics of such ion-bombarded polymers are associated with the detail of the electronic structure at the valence band from theoretical and experimental viewpoints.In recent studies using deMon density-functional the- † To whom correspondence should be addressed.ory (DFT) program 10 which uses the idea of transitionstate, 11 Endo and co-workers 12-18 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)) 12-18 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 u...

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Theoretical X-ray photoelectron spectra of polymers by deMon DFT calculations using the model dimers

Cited by 32 publications

References 46 publications

Theoretical auger electron spectra of polymers by density functional theory calculations using model dimers

Theoretical auger electron spectra of polymers by density functional theory calculations using model dimers

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

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

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