The dependence of the near-edge X-ray absorption fine structure (NEXAFS) spectrum of molecules on the photon electric field direction is investigated by means of first-principles simulations based on density functional theory with the transition-potential approach. In addition to the well-known dependence of the NEXAFS resonances on the orientation of the electric field with respect to the molecular plane, we demonstrate that for planar molecules with sufficient in-plane anisotropy such as pentacene a dichroic effect is found with a splitting of the sigma* resonance as a function of the azimuthal orientation of the photon electric field in the molecular plane. The sigma* splitting is investigated as a function of the length of acenes and closely related molecules. A proper assignment of such spectral features guided by theory together with variable polarization experiments may allow one to completely determine the orientation of molecules at interfaces.

Azimuthal Dichroism in Near-Edge X-ray Absorption Fine Structure Spectra of Planar Molecules / Fratesi, Guido; Lanzilotto, Valeria; Floreano, Luca; Brivio, Gian Paolo. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - 117:13(2013), pp. 6632-6638. [10.1021/jp312569q]

Azimuthal Dichroism in Near-Edge X-ray Absorption Fine Structure Spectra of Planar Molecules

Lanzilotto, Valeria;
2013

Abstract

The dependence of the near-edge X-ray absorption fine structure (NEXAFS) spectrum of molecules on the photon electric field direction is investigated by means of first-principles simulations based on density functional theory with the transition-potential approach. In addition to the well-known dependence of the NEXAFS resonances on the orientation of the electric field with respect to the molecular plane, we demonstrate that for planar molecules with sufficient in-plane anisotropy such as pentacene a dichroic effect is found with a splitting of the sigma* resonance as a function of the azimuthal orientation of the photon electric field in the molecular plane. The sigma* splitting is investigated as a function of the length of acenes and closely related molecules. A proper assignment of such spectral features guided by theory together with variable polarization experiments may allow one to completely determine the orientation of molecules at interfaces.
2013
molecular sel-assembly; NEXAS dichroism; DFT;
01 Pubblicazione su rivista::01a Articolo in rivista
Azimuthal Dichroism in Near-Edge X-ray Absorption Fine Structure Spectra of Planar Molecules / Fratesi, Guido; Lanzilotto, Valeria; Floreano, Luca; Brivio, Gian Paolo. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - 117:13(2013), pp. 6632-6638. [10.1021/jp312569q]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1279475
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