Azimuthal Dichroism in Near-Edge X - ray Absorption Fine Structure Spectra of Planar Molecules: 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 computed with a splitting of the σ* resonance as a function of the azimuthal orientation of the photon electric field in the molecular plane. The σ* 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. [1] G. Fratesi, V. Lanzilotto, L. Floreano, and G. P. Brivio, J. Phys. Chem. C (2013), vol. 117, pages 6632-6638

Azimuthal dichroism in near-edge X - ray absorption fine structure spectra of planar molecules / G. Fratesi, V. Lanzilotto, L. Floreano, G.P. Brivio. ((Intervento presentato al convegno Italian National Conference on Condensed Matter Physics tenutosi a Milano nel 2013.

Azimuthal dichroism in near-edge X - ray absorption fine structure spectra of planar molecules

G. Fratesi
Primo
;
2013

Abstract

Azimuthal Dichroism in Near-Edge X - ray Absorption Fine Structure Spectra of Planar Molecules: 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 computed with a splitting of the σ* resonance as a function of the azimuthal orientation of the photon electric field in the molecular plane. The σ* 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. [1] G. Fratesi, V. Lanzilotto, L. Floreano, and G. P. Brivio, J. Phys. Chem. C (2013), vol. 117, pages 6632-6638
Settore FIS/03 - Fisica della Materia
Settore CHIM/02 - Chimica Fisica
http://www.fisi.polimi.it/it/fismat2013/submission/view/229
Azimuthal dichroism in near-edge X - ray absorption fine structure spectra of planar molecules / G. Fratesi, V. Lanzilotto, L. Floreano, G.P. Brivio. ((Intervento presentato al convegno Italian National Conference on Condensed Matter Physics tenutosi a Milano nel 2013.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/250669
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