X-ray Absorption Fine Structure in Embedded Atoms

TL;DR

This paper identifies and confirms a new oscillatory feature in X-ray absorption spectra caused by scattering within embedded atoms, offering a novel method to probe chemical bonding and exchange effects.

Contribution

It introduces the concept of atomic-XAFS (AXAFS), demonstrating its existence through calculations and measurements, and highlights its significance in understanding chemical and electronic interactions.

Findings

AXAFS arises from scattering within embedded atoms

AXAFS can dominate multi-electron excitation contributions

AXAFS is sensitive to chemical effects

Abstract

Oscillatory structure is found in the atomic background absorption in x-ray-absorption fine structure (XAFS). This atomic-XAFS or AXAFS arises from scattering within an embedded atom, and is analogous to the Ramsauer-Townsend effect. Calculations and measurements confirm the existence of AXAFS and show that it can dominate contributions such as multi-electron excitations. The structure is sensitive to chemical effects and thus provides a new probe of bonding and exchange effects on the scattering potential.