Resonances in the <i>K</i> shell excitation spectra of benzene and pyridine: Gas phase, solid, and chemisorbed states

Horsley, J. A.; Stöhr, J.; Hitchcock, Adam P.; Newbury, D. C.; Johnson, Allen L.; Sette, F.

doi:10.1063/1.449601

Cited by 370 publications

(290 citation statements)

References 30 publications

Supporting

Mentioning

247

Contrasting

Unclassified

Order By: Relevance

“…They agree reasonably well with those acquired using X-ray absorption spectroscopy [3]. Most of the peaks can be assigned to empty orbitals in benzene, following Horsley et al [4]. Thus the spectrum from polystyrene is dominated by its benzene rings.…”

supporting

confidence: 75%

Recent Studies of Near-Edge Structure

Brown

Walsh

Dray

et al. 1995

Microsc. Microanal. Microstruct.

View full text Add to dashboard Cite

Abstract. 2014 The extent to which near-edge structure depends upon long-range order is explored using polymeric systems, where one can vary the disposition of side-groups and the degree of crystallinity and compare the resulting spectra. Carbon K-edges for polystyrene in atactic and isotactic forms are compared; the former is amorphous and the latter crystalline. Differences between the spectra are very slight but observable, and are attributed to bond orientation effects and to interaction between closely-spaced hydrogens bonded to neighbouring benzene rings and to the backbone. The quality of the spectra collected at doses of less than 300 e-nm-2 from a few square microns compares favourably with previously published EXAFS data. Another example of near-edge structure is provided by segregated species. The case of iron segregated to boundaries in Zr-Nb alloys is of intense interest to the nuclear industry. An attempt has been made to interpret observed fine structure in terms of structure from reference intermetallic compounds. It seems that the fine structure displayed by the segregated iron is different from that displayed by pure metallic iron or by known compounds with Zr, but more akin to ZrNbFe.Microsc. Microanal. Microstruct. 6 (1995) Figure 1. A benzene ring is attached to every other carbon atom of the carbon backbone. Each carbon atom has two different bonds to which the benzene ring can be attached. In isotactic polystyrene the rings are all attached to the same side of the carbon backbone. This isomer can be produced in both amorphous and crystalline forms. In atactic polystyrene the benzene rings are distributed at random on both sides of the carbon chain, which precludes the possibility of crystallization. Polystyrene was chosen because, by comparison to many polymers, it is less sensitive to irradiation damage by an electron beam. Spectra were acquired from amorphous atactic polystyrene, amorphous isotactic polystyrene and crystalline isotactic polystyrene. The amorphous films were produced by dissolving the polystyrene in toluene and drawing out a film on a glass slide. The crystals were produced as described by Tanzawa [1] and deposited from solution directly onto commercially produced SiO films on Cu

show abstract

supporting

confidence: 75%

Recent Studies of Near-Edge Structure

Brown

Walsh

Dray

et al. 1995

Microsc. Microanal. Microstruct.

View full text Add to dashboard Cite

show abstract

“…26 Above the carbonyl transition C 1s f σ* transitions are assigned in accordance with previous assignments. 7,25 3.1.3.…”

Section: Distinguishing Urea and Carbamatementioning

confidence: 99%

Near-Edge X-ray Absorption Fine Structure Spectroscopy of MDI and TDI Polyurethane Polymers

et al. 1999

View full text Add to dashboard Cite

The sensitivity of near-edge X-ray absorption fine structure (NEXAFS) to differences in key chemical components of polyurethane polymers is presented. Carbon 1s NEXAFS spectra of polyurethane polymers made from 4,4′-methylene di-p-phenylene isocyanate (MDI) and toluene diisocyanate (TDI) isocyanate monomers illustrate that there is an unambiguous spectroscopic fingerprint for distinguishing between MDIbased and TDI-based polyurethane polymers. NEXAFS spectra of MDI and TDI polyurea and polyurethane models show that the urea and carbamate (urethane) linkages in these polymers can be distinguished. The NEXAFS spectroscopy of the polyether component of these polymers is discussed, and the differences between the spectra of MDI and TDI polyurethanes synthesized with polyether polyols of different molecular composition and different molecular weight are presented. These polymer spectra reported herein provide appropriate model spectra to represent the pure components for quantitative microanalysis.

show abstract

“…33 There is, however, a known tendency for resonances observed in core ionization to be shifted by a few eV to lower kinetic energy due to interaction with the core hole, so that * shape resonances might still be expected in valence shell ionization. However, in the high symmetry ͑D 6h ͒ of benzene, dipole selection rules determine that a b 2g continuum can only be accessed by ionization of b 1u or e 2u orbitals, and the only pertinent valence shell ionization is thus 2b 1u −1 .…”

Section: -7mentioning

confidence: 99%

An unusual π* shape resonance in the near-threshold photoionization of S1 para-difluorobenzene

Bellm

Davies

Whiteside

et al. 2005

The Journal of Chemical Physics

View full text Add to dashboard Cite

Previously reported dramatic changes in photoelectron angular distributions ͑PADs͒ as a function of photoelectron kinetic energy following the ionization of S 1 p-difluorobenzene are shown to be explained by a shape resonance in the b 2g symmetry continuum. The characteristics of this resonance are clearly demonstrated by a theoretical multiple-scattering treatment of the photoionization dynamics. New experimental data are presented which demonstrate an apparent insensitivity of the PADs to both vibrational motion and prepared molecular alignment, however, the calculations suggest that strong alignment effects may nevertheless be recognized in the detail of the comparison with experimental data. The apparent, but unexpected, indifference to vibrational excitation is rationalized by considering the nature of the resonance. The correlation of this shape resonance in the continuum with a virtual * antibonding orbital is considered. Because this orbital is characteristic of the benzene ring, the existence of similar resonances in related substituted benzenes is discussed.

show abstract

Resonances in the K shell excitation spectra of benzene and pyridine: Gas phase, solid, and chemisorbed states

Cited by 370 publications

References 30 publications

Recent Studies of Near-Edge Structure

Recent Studies of Near-Edge Structure

Near-Edge X-ray Absorption Fine Structure Spectroscopy of MDI and TDI Polyurethane Polymers

An unusual π* shape resonance in the near-threshold photoionization of S1 para-difluorobenzene

Contact Info

Product

Resources

About