Orientation of aromatic hydrocarbons on metal surfaces as determined by nexafs

Yannoulis, P.; Dudde, R.; Frank, K. H.; Koch, E. E.

doi:10.1016/s0039-6028(87)80476-4

Cited by 118 publications

(64 citation statements)

References 17 publications

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“…However, in the subsequently recorded images several molecules appear rearranged, i.e., tilted in other directions, presumably induced by the electric field applied during the scans. Yannoulis et al also measured a tilt angle for coronene molecules of (16 ± 10)°on the Ag(111) surface via near-edge X-ray absorption fine structure (NEXAFS) [30]. While this value has to be considered with caution it seems indeed very unlikely that the aromatic framework is oriented parallel to the Ag(111) surface, and comparable values might be expected here for coronene on Cu(111).…”

Section: Coronene On Cu(111)supporting

confidence: 65%

Growth of coronene on (100)- and (111)-surfaces of fcc-crystals

et al. 2015

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Section: Coronene On Cu(111)supporting

confidence: 65%

Growth of coronene on (100)- and (111)-surfaces of fcc-crystals

et al. 2015

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“…The comparison of copper-phthalocyanine adsorbed on MoS 2 and HOPG [4] shows that even interaction with weakly bonding van der Waals substrates can cause changes in the STM image. However, also a geometrical effect such as the tilt of the molecular plane found for coronene on Ag(111) by means of STM [5,6] and NEXAFS [7] cannot be completely ruled out.…”

Section: Resultsmentioning

confidence: 98%

STM and STS of coronene on HOPG(0001) in UHV - adsorption of the smallest possible graphite flakes on graphite

Lackinger

Griessl

Heckl

et al. 2002

Analytical and Bioanalytical Chemistry

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The adsorption of the aromatic molecule hexabenzobenzene (coronene) on an HOPG(0001) surface was investigated under UHV conditions by means of variable temperature scanning tunneling microscopy (STM) and spectroscopy (STS). Imaging on a mesoscopic scale showed a distribution of coronene islands. These islands are mobile on the surface and can be pinned at step-edges. Zooming in on areas apart from the islands reveals an hexagonal arrangement of coronene molecules in a closed layer. Submolecular resolved molecules consist of bright spots with varying intensity. This variation in intensity is explained with the commensurability of the adlayer. STS investigations were performed for various tip-sample distances, adjusted by the tunneling current setpoint. A gap can be seen for every setpoint, but its width is dependent on the setpoint. The gap for the largest tip-sample distance and therefore the smallest tip-sample interaction is compared with the theoretical value.

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“…16 Cls-n* transition occurs when the electric vector of the incident beam is perpendicular to the ring plane, as clearly demonstrated in extremely thin films of a series of aromatic hydrocarbons, including benzene and naphthalene, formed on Ag(lll) and Cu(l00). 33 The 130 aromatic ring planes of PET and PEN tend to become parallel to the film plane when the films are stretched, particularly when biaxially drawn, as revealed by X-ray diffraction. 34 • 35 Peak "A" at 285.6 e V should thus be more intense when the film plane makes a smaller angle with incident beam, as long as the skin portion of the film has similar molecular orientation as the interior.…”

Section: Absorption Spectra Near Carbon K-edgementioning

confidence: 99%

Core Electron Absorption Spectra of Poly(ethylene terephthalate) and Poly(ethylene 2,6-naphthalate) Films

Ouchi

Nakai

Kamada

et al. 1995

Polym J

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ABSTRACT:Absorption spectra by means of the transmission method and total electron yield method were obtained for poly(ethylene terephthalate) (PET) and poly(ethylene 2,6-naphthalate) (PEN) films in the soft X-ray region by use of synchrotron radiation. The absorptions at 285.6 and 289.3 eV were due to Cls->n* transitions, showing stronger intensities for obliquely incident light than for normal. Broad absorptions consisting of humps at 293.5, 296.9, and 304.5 eV were originated in Cls->cr* transitions, having stronger intensities for an incident beam normal to the film plane than for oliquely incident light. The strong absorption of core electrons of oxygen appeared near 540.5 eV and was attributed to an Ols--.cr* transition; a neighboring peak at 532.3 eV was sensitive to the incident angle and was assigned as O!s--.n* transition. Oscillator strength and other optical features are briefly discussed. KEY WORDSPolarized Absorption Spectra / Synchrotron Radiation / Poly(ethylene terephthalate) / Poly(ethylene naphthalate) / Biaxially Oriented Films/ Total Electron Yield/ Transmission / Carbon K Edge/ Oxygen K Edge / Oscillator Strength / Absorption and em1ss10n spectra of the valence electrons of poly(ethylene terephthalate) (PET) have been studied for the clarification of photochemical and photophysical features. 1 -10 The polarized absorption and reflection spectra of uniaxially drawn PET films were analyzed in detail in the ultraviolet region down to 190 nm (or up to about 6.5 eV); the transition energies observed therein were compared with theoretical values from molecular orbital calculations. 8 -i O The emission spectra were measured and their origins were discussed. 4 -8 • 1° Furthermore, X-ray photoelectron spectrum of the valence band of PET in the binding energy up to about 30 e V was obtained by use of synchrotron radiation, together with simulation calculations 11 • 12 ; conformational effects were revealed in the spectra. 12 The spectroscopy related to the core electrons, whose energy corresponds to far ultraviolet or soft X-ray, has been studied for PET by means of X-ray photoelectron spectroscopy (XPS); whereby, assignments were given for three kinds of carbon ( carbonyl, aromatic, and aliphatic) and two kinds of oxygen (carbonyl and ester). 12 -15 Recently, electron energy loss spectroscopy (EELS) was applied to PET 16 ; spectral features of this polymer were discussed with the aid of core excitation spectra of small molecule analogues and extended Ruckel molecular orbital calculations of dimethylterephthalate.Absorption spectra of core electrons of polymers were first obtained by Seki et a/ 1 7 for very thin oriented syndiotactic 1,2-polybutadiene films. By use of a synchrotron radiation, they observed anisotropic absorp-127

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Orientation of aromatic hydrocarbons on metal surfaces as determined by nexafs

Cited by 118 publications

References 17 publications

Growth of coronene on (100)- and (111)-surfaces of fcc-crystals

Growth of coronene on (100)- and (111)-surfaces of fcc-crystals

STM and STS of coronene on HOPG(0001) in UHV - adsorption of the smallest possible graphite flakes on graphite

Core Electron Absorption Spectra of Poly(ethylene terephthalate) and Poly(ethylene 2,6-naphthalate) Films

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