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

TitleTheoretical X-ray photoelectron spectra of polymers by deMon DFT calculations using the model dimers
Publication TypeJournal Article
Year of Publication2000
AuthorsOtsuka, T, Endo, K, Suhara, M, Chong, DP
JournalJournal of Molecular Structure
Volume522
Pagination47-60
Date PublishedApr
Type of ArticleArticle
ISBN Number0022-2860
KeywordsC1S SPECTRA, core-electron spectra, deMon DFT calculations, DENSITY-FUNCTIONAL CALCULATION, ELECTRON-BINDING-ENERGIES, LOCAL-DENSITY, MOLECULES, POLY(METHYL METHACRYLATE), POLY(VINYL ALCOHOL), POLYMERS, SEMIEMPIRICAL MO THEORY, VALENCE-BAND, XPS CORE
Abstract

Core-electron spectra of 15 polymers [(CH2CH2)(n) (PE), (CH2CH(CH3))(n) (PP), (CH2CH2NH)(n) (PEI), (CH2CH2O)(n) (PEG), (CH2CH(OCH3))(n) (PVME), (CH2CHF)(n) (PVF), (CH2CF2)(n) (PVDF), (CF2CF2)(n) (PTFE), (CH2CH(CN))(n) (PAN), (CH2C(CH3)(CN))(n) (PMAN), (CH2CH2S)(n) (PETHS), (CH2CHCl)(n) (PVC), (CH2CCl2)(n) (PVDC), (Si(CH3)(2))(n) (PDMS), (Si(CH3)(2)O)(n) (PDMSO)], and valence photoelectron spectra (XPS) of the six polymers (PP, PEI, PAN, PMAN, PVME, PTFE) were obtained by deMon density-functional theory (DFT) calculations using the model dimers. The core-electron spectra were simulated with the Gaussian lineshape functions with fixed linewidths of 0.5, and 1.0 eV for each C1sd, and (N1s, O1s, F1s) MO value, respectively, and calculated Al-K alpha Valence photoelectron spectra were obtained using Gaussian lineshape functions of an approximate linewidth (0.08I(k)): I-k(I-FL) = I-k’ - WD, as indicated in previous works. The vertical ionization potential I-k’ and each core-electron binding energy (CEBE) were calculated by restricted generalized diffuse ionization (rGDI) and unrestricted generalized transition-state (uGTS) models, respectively. The theoretical core-electron spectra showed better agreement with the experimental ones of the polymers than those due to Koopmans’ theorem. The difference between the calculated and the experimental CEBEs reflected the reasonable WDs of the polymers. (C) 2000 Elsevier Science B.V. All rights reserved.

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