A Comparative Study of the Valence Electronic Excitations of N_2 by Inelastic X-ray and Electron Scattering

TL;DR

This study compares valence electronic excitation spectra of N_2 obtained via inelastic X-ray and electron scattering, revealing significant discrepancies outside the dipole limit due to intra-molecular multiple scattering effects.

Contribution

It highlights the importance of intra-molecular multiple scattering in electronic excitation spectra, challenging the assumption that different probes yield identical dynamical structure factors.

Findings

Strong disagreements observed outside the dipole scattering limit

Multiple scattering effects increase with atomic number

Probes do not always produce equivalent spectra as previously assumed

Abstract

Bound state, valence electronic excitation spectra of N_2 are probed by nonresonant inelastic x-ray and electron scattering. Within the usual theoretical treatments, dynamical structure factors derived from the two probes should be identical. However, we find strong disagreements outside the dipole scattering limit, even at high probe energies. This suggests an unexpectedly important contribution from intra-molecular multiple scattering of the probe electron from core electrons or the nucleus. These effects should grow progressively stronger as the atomic number of the target species increases.