Coherent Stimulated X-ray Raman Spectroscopy; Attosecond Extension of RIXS

TL;DR

This paper introduces a method for calculating resonant inelastic X-ray Raman scattering signals using Green's functions and configuration interaction, enabling attosecond time resolution without complex many-body state calculations.

Contribution

It presents a novel theoretical framework that simplifies the calculation of X-ray Raman signals by leveraging standard electronic structure tools and avoiding complex many-body state computations.

Findings

Efficient calculation of resonant inelastic X-ray Raman signals.

Expression of signals as overlaps of electron-hole wavepackets.

Extension of RIXS to attosecond timescales.

Abstract

Spontaneous and stimulated resonant inelastic X-ray Raman scattering signals are calculated using the Keldysh-Schwinger closed-time path loop and expressed as overlaps of Doorway and Window electron-hole wavepackets. These are recast in terms of the one-particle Green's functions and expansion coefficients of configuration interaction singles for valence excitations, which can be obtained from standard electronic structure codes. Calculation for many-body states of ground and core-excited system is avoided.