Carbon 1s photoelectron spectroscopy of six-membered cyclic hydrocarbons

Oltedal, Velaug Myrseth; Børve, Knut J.; Sæthre, Leif J.; Thomas, T. D.; Bozek, John D.; Kukk, E.

doi:10.1039/b405109b

Cited by 29 publications

(43 citation statements)

References 27 publications

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“…5 Additional details of these procedures are given elsewhere. 6,7 From these results the Franck-Condon factors for each vibrational mode have been calculated using the harmonic oscillator approximation, and these factors are convoluted to give the combination modes and, hence, an overall profile. Each profile includes all transitions with intensities predicted to be stronger than 0.001% of the most intense line.…”

Section: Theoretical Detailsmentioning

confidence: 99%

Additivity of Substituent Effects. Core-Ionization Energies and Substituent Effects in Fluoromethylbenzenes

Carroll

Thomas²,

Sæthre³

et al. 2009

J. Phys. Chem. A

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Carbon 1s ionization energies have been measured for all of the carbon atoms in eight fluoromethylbenzenes. Enthalpies of protonation have been calculated for protonation at all of the ring carbons in the same molecules. These data together with previously reported data on fluorobenzenes and methylbenzenes provide the basis for studying the additivity of substituent effects and the correlation between enthalpies of protonation with core-ionization energies. Although a linear additivity model accounts reasonably well for both the ionization energies and the enthalpies of protonation, a better description, especially for the enthalpies, is obtained by inclusion of nonlinear terms that account for interactions between two substituents on the same molecule. There are families of nearly parallel correlation lines between enthalpies of protonation and core-ionization energies. The existence of several families can be primarily understood in terms of the linear additivity picture and more completely understood when the nonlinear terms are taken into account. The role of the methyl group as a polarizible pi-electron donor is contrasted with the role of fluorine, which is a substituent of low polarizibility that acts to withdraw electrons from the adjacent carbon and to donate electrons through resonance to the ring. The role of the hydrogen atoms as pi-electron acceptors in the protonated species is illustrated.

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Section: Theoretical Detailsmentioning

confidence: 99%

Additivity of Substituent Effects. Core-Ionization Energies and Substituent Effects in Fluoromethylbenzenes

Carroll

Thomas²,

Sæthre³

et al. 2009

J. Phys. Chem. A

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“…2͑B͒ and 4͑B͒ indi-cate calculated ionization thresholds which are not directly accessible by the present experiments. However, Oltedal et al 46 have recently published experimental atom-resolved IPs for C 6 H n ͑n = 6, 8, 10, 12͒ molecules. These values are compared in Table IV with our theoretical data obtained from DFT calculations within the ⌬ self-consistent-field ͑⌬SCF͒ approach.…”

Section: A Assignment Of Spectral Featuresmentioning

confidence: 99%

“…This idea has been used to evaluate a total "theoretical" peak A for 1,3cyclohexadiene in analogy to a procedure described in Ref. 46. Here the experimental peak A for cyclohexene ͓Fig.…”

Section: E Vibrational Analysismentioning

confidence: 99%

Spectroscopic analysis of small organic molecules: A comprehensive near-edge x-ray-absorption fine-structure study of C6-ring-containing molecules

Kolczewski

Püttner

Martins

et al. 2006

The Journal of Chemical Physics

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We report high-resolution C 1s near-edge x-ray-absorption fine-structure (NEXAFS) spectra of the C6-ring-containing molecules benzene (C6H6), 1,3- and 1,4-cyclohexadiene (C6H8), cyclohexene (C6H10), cyclohexane (C6H12), styrene (C8H8), and ethylbenzene (C8H10) which allow us to examine the gradual development of delocalization of the corresponding pi electron systems. Due to the high experimental resolution, vibrational progressions can be partly resolved in the spectra. The experimental spectra are compared with theoretical NEXAFS spectra obtained from density-functional theory calculations where electronic final-state relaxation is accounted for. The comparison yields very good agreement between theoretical spectra and experimental results. In all cases, the spectra can be described by excitations to pi*- and sigma*-type final-state orbitals with valence character, while final-state orbitals of Rydberg character make only minor contributions. The lowest C 1s-->1pi* excitation energy is found to agree in the (experimental and theoretical) spectra of all molecules except for 1,3-cyclohexadiene (C6H8) where an energy smaller by about 0.6 eV is obtained. The theoretical analysis can explain this result by different binding properties of this molecule compared to the others.

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“…In large part this comes from the vast amount of experimental spectra in the core region obtained at high photon energies: the ESCA period of the Mg K␣ and Al K␣ spectra opened up by Siegbahn and co-workers. [3][4][5] However, even at the lower energies required to improve resolution, the statistical ratio is generally assumed, for example, in the deconvolution of the spectra. 2 The study of core ionizations has received a new impulse by the availability of tunable radiation in the soft x-ray range with high fluxes and very high resolution at synchrotron radiation laboratories.…”

Section: Introductionmentioning

confidence: 99%

Branching ratio deviations from statistical behavior in core photoionization

Tommaso

Decleva

2005

The Journal of Chemical Physics

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Accurate calculations of carbon 1s photoionization cross sections have been performed at the density functional level with the B-spline linear combination of atomic orbitals approach. The molecules considered are FC[triple bond]CH, FC[triple bond]CCH3, FC[triple bond]CCN, F2C=CH2, CF3COOCH2CH3, and C3H5O. The variation of the branching ratios relative to inequivalent C 1s ionizations have been evaluated from threshold to about 100 eV photoelectron kinetic energy. Large deviations from the statistical ratios are observed at low energies, which remain often significant several tens of eV above threshold. The importance of taking into account core branching ratios for peak deconvolution and quantitative analysis, as well as an additional tool for structural information, is pointed out. Strong shape resonant effects are found to largely cancel in branching ratios. Their nature and variation along the series is analyzed in the framework of excitations into sigma* valence orbitals.

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Carbon 1s photoelectron spectroscopy of six-membered cyclic hydrocarbons

Cited by 29 publications

References 27 publications

Additivity of Substituent Effects. Core-Ionization Energies and Substituent Effects in Fluoromethylbenzenes

Additivity of Substituent Effects. Core-Ionization Energies and Substituent Effects in Fluoromethylbenzenes

Spectroscopic analysis of small organic molecules: A comprehensive near-edge x-ray-absorption fine-structure study of C6-ring-containing molecules

Branching ratio deviations from statistical behavior in core photoionization

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