Interaction of photons with plasmas and liquid metals: photoabsorption and scattering

TL;DR

This paper develops unified formulas for photon interactions with plasmas and liquid metals, detailing how nuclear, free-electron, and core-electron motions influence photoabsorption and scattering, aiding experimental analysis.

Contribution

It introduces a comprehensive framework linking photoabsorption and scattering processes with electron-ion dynamics, including formulas for anomalous X-ray scattering in liquid metals.

Findings

Derived unified formulas for photoabsorption and scattering.

Clarified the roles of nuclear, free-electron, and core-electron motions.

Provided analysis methods for various experimental DSF observations.

Abstract

Formulas to describe the photoabsorption and the photon scattering by a plasma or a liquid metal are derived in a unified manner with each other. It is shown how the nuclear motion, the free-electron motion and the core-electron behaviour in each ion in the system determine the structure of photoabsorption and scattering in an electron-ion mixture. The absorption cross section in the dipole approximation consists of three terms which represent the absorption caused by the nuclear motion, the absorption owing to the free-electron motion producing optical conductivity or inverse Bremsstrahlung, and the absorption ascribed to the core-electron behaviour in each ion with the Doppler correction. Also, the photon scattering formula provides an analysis method for experiments observing the ion-ion dynamical structure factor (DSF), the electron-electron DSF giving plasma oscillations, and the core-electron DSF yielding the X-ray Raman (Compton) scattering with a clear definition of the background scattering for each experiment, in a unified manner. A formula for anomalous X-ray scattering is also derived for a liquid metal. At the same time, Thomson scattering in plasma physics is discussed from this general point of view.