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 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.
Azimuthal dichroism in near-edge X-ray absorption fine structure spectra of planar molecules / G. Fratesi, V. Lanzilotto, L. Floreano, G.P. Brivio. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - 117:13(2013 Mar 12), pp. 6632-6638. [10.1021/jp312569q]
Azimuthal dichroism in near-edge X-ray absorption fine structure spectra of planar molecules
G. FratesiPrimo
;
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 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.File | Dimensione | Formato | |
---|---|---|---|
JPCC_2013_v117_p6632_Fratesi_azimuthal_dichroism_NEXAFS_planar_molecules.pdf
accesso riservato
Tipologia:
Publisher's version/PDF
Dimensione
1.63 MB
Formato
Adobe PDF
|
1.63 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.