Generalization of Slater’s transition state concept

Williams, A. R.; Groot, R.A. de; Sommers, C.

doi:10.1063/1.431382

Cited by 147 publications

(80 citation statements)

References 13 publications

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“…As stated in the previous work, 4 in the generalized transition-states (GTS) method, Williams et al 10 proposed the extension of Slater's transition-state idea 11 and approximated the endothermicity…”

Section: Cebes Of Cls Due To the Slater's Transition State Using Dft mentioning

confidence: 99%

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

Endo

Maeda

Kaneda

1997

Polym J

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Section: Cebes Of Cls Due To the Slater's Transition State Using Dft mentioning

confidence: 99%

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

Endo

Maeda

Kaneda

1997

Polym J

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“…Ifwe define the first derivative (F(x)=dE(x)/dx), in the generalized transition-state (GTS) method, Williams et al 31 propposed the use of…”

Section: Cebes Of Cls Due To Slater's Concept Of the Transitionstate mentioning

confidence: 99%

Simulation of C1s Spectra of C- and O-Containing Polymers in XPS by ab initio MO Calculations Using Model Oligomers

Endo

Maeda

Aida

1997

Polym J

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ABSTRACT:Cls spectra of molecules [CH2 =CH(COOH), CH2 =CH---COOCH 3 , CH 2 =C(CH 3 )COOCH 3 , CH 3 -CH-(CH3)COOCH3] in gas and fifteen polymers . (R = H, CH3, OH, OCH 3, COCH3, COOH, OCOCH 3 , COOCH 3 ), ((CHh-O). (k = 1---4), (CHRCO-O). (R= H, CH3), and (CH 2-C(CH 3)COOCH3).] in X-ray photoelectron spectroscopy (XPS) were simulated from Koopmans' theorem by ah initio MO calculations of HONDO7 program using the model oligomers. The calculated Cls spectra were obtained using Gaussian lineshape functions of each fixed linewidth of 0.54 and 1.3 eV for the gas molecules and the oligomers, respectively. The theoretical spectra showed fairly good accordance with the experimental spectra, although the shifted values were used as 14.4 and 21.0 eV for core Cls energy levels of the gas molecules and the model oligomers, respectively. The difference between the shifted values (21.0 and 14.4eV) approaches to the WD (5.2~6.4eV) often polymers as obtained by deMon density-functional calculations using model molecules with scaled-pVTZ basis set. This is due to the relation of solid effects between the experimental core-electron binding energies of polymers and theoretical MO eigenvalues of the oligomer models, as stated in the previous work.KEY WORDS X-Ray Photoelectron Spectroscopy/ Cls Spectra/ Ab Jnitio MO/ Spectral Simulation/ Koopmans' Theorem / O-Containing Polymer/ Work Function/ We have currently reported on the simulation of Xray photoelectron spectra of polymers by MO calculations using the model molecules. 1 -10 The theorem of the MO calculations can be classified into three typical cases: (a) the Koopmans' theorem, (b) delta-SCF, and (c) Slaters' concept 11 of the transition-state. In the case (a), we offered a good analysis 2 -4 of Cls spectra with Koopmans' values for four polymers [(CH2-CHR)n (R=OH, COOH, OCOCH 3 ) and (CH 2 -C(CH 3 )COO-CH3)nJ, although the shifted value was used as 21.0 eV for core Cls energy levels of the model oligomers. The reason relies on it that the differences between core energy levels as obtained using calculations of the neutral parent molecules approximate the ones as observed for the ionized molecules in XPS, although the nuclear positive charges strongly attract the core electrons in the deep potential of the ionized state. However, in the case of valence electron spectra, the energy scale of the simulated spectra 12 -14 using the Koopmans' theorem had to be contracted and shifted for a good fit with the observed spectra. This means that the energy levels in valence electron region of a ionized molecule are narrowed more than the Koopmans' values in the range of the neutral parent molecule, since there are valence electrons in the shallow potential.The method of delta-SCF (case (b)) gave quite reliable values 15 • 16 of the core-electron binding energies (CEBEs), but suffers from occasional failures. In recent papers, 5 -10 we have performed the theoretical better assignment of valence-band spectra for 60 polymers due to Slater's idea of the transition-state (case (c)) by semiemp...

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“…The method employs an unrestricted generalized transition-state (uGTS) model. 28 Pulfer et al have confirmed the reliability of the method with a total of seventy-six cases. 29 More recently, a more reliable method, called ∆E KS (PW86-PW91)/cc-pCVTZ, was found by Cavigliasso and Chong.…”

Section: Introductionmentioning

confidence: 71%

Is HAM/3 (hydrogenic atoms in molecules, version 3) a semiempirical version of dft (density functional theory) for ionization processes?

Takahata¹,

Chong²

2004

J. Braz. Chem. Soc.

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Nós calculamos os potenciais de ionização verticais (VIPs) de nove moléculas pequenas, bem como, os potenciais de uracil e do C 2 F 2 usando diferentes métodos: i) semi-empírico HAM/3; ii) semi-empírico AM1; iii) não empírico Teoria do Funcional de Densidade (TFD) com os modelos uDI(B88-P86)/cc-pVTZ e -ε(SAOP)/TZP; iv) ab initio HF/cc-pVTZ. Os resultados numéricos obtidos com HAM/3 são mais próximos dos resultados obtidos com o TFD do que o Hartree-Fock (HF). Nós também calculamos as energias de ligação de elétrons do caroço (CEBE) da anilina, nitrobenzeno, e p-nitroanilina com o HAM/3 e a TFD empregando o método ∆E. O modelo de DFT designado como ∆E KS (PW86-PW91)/TZP produziu resultados precisos de CEBE, com desvio médio absolutos de 0,14 eV. Enquanto que a magnitude absoluta dos CEBEs calculados pelo método HAM/3 tem um erro de menos de 3 eV, os deslocamentos químicos (∆CEBE) têm erros menores que 0,55 eV. Mesmo que os resultados de CEBE não apresentem uma resposta definitiva à pergunta do título, as tendências nos VIPs indicam que o HAM/3 não se aproxima do TFD com potenciais de troca-correlação precisos, mas indicam uma proximidade com funcionais semelhantes ao B88-P86.We calculated valence-electron vertical ionization potentials (VIPs) of nine small molecules, plus uracil and C 2 F 4 , by several different methods: semiempirical HAM/3 and AM1 methods, different nonempirical DFT models such as uDI(B88-P86)/cc-pVTZ and -ε(SAOP)/TZP, and ab initio Hartree-Fock (HF) /cc-pVTZ. HAM/3 reproduced numerical values more closely to those calculated by the nonempirical DFTs than to those obtained by HF method. Core-electron binding energies (CEBEs) of aniline, nitrobenzene and p-nitro aniline, were also calculated by HAM/3 and nonempirical ∆FT using DE method. A nonempirical DFT model, designated as ∆E KS (PW86-PW91)/TZP model, resulted accurate CEBEs (average absolute deviation of 0.14 eV) with high efficiency. Although absolute magnitude of HAM/3 CEBEs has error as much as 3 eV, the error in the chemical shifts ∆CEBE is much smaller at 0.55 eV. While the CEBE results do not lead to any definite answer to the question in the title, the trends in valence-electron VIPs indicate that HAM/3 does not approximate DFT with accurate exchange-correlation potentials, but seems to simulate approximate functionals such as B88-P86.Keywords: HAM/3, DFT, vertical ionization potential, CEBE, ESCA IntroductionThe semiempirical molecular orbital (MO) method known as Hydrogenic Atoms in Molecules, Version 3 (HAM/3) was developed by group of Lindholm and coworkers in 1977. 1 The method has been successfully applied to the calculation of mainly vertical ionization potentials (VIPs), excitation energies, and electron affinities of wide variety of molecules. Some selected works are listed in references 2-7. However, extensions of HAM/3 to the calculation of X-ray emission spectra, 8 Auger electron spectra, 9 valence-electron shake-up satellites, 10 core-electron shake-up satellites, 11 and relative intensities for valence region of X-ray p...

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Generalization of Slater’s transition state concept

Cited by 147 publications

References 13 publications

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 C1s Spectra of N-, O-, and X-Containing Polymers in X-Ray Photoelectron Spectroscopy by ab initio Molecular Orbital Calculations Using Model Molecules

Simulation of C1s Spectra of C- and O-Containing Polymers in XPS by ab initio MO Calculations Using Model Oligomers

Is HAM/3 (hydrogenic atoms in molecules, version 3) a semiempirical version of dft (density functional theory) for ionization processes?

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