The attosecond regime of impulsive stimulated electronic Raman excitation

TL;DR

This paper investigates the mechanisms of attosecond impulsive stimulated electronic Raman scattering, revealing that continuum transitions dominate over autoionizing resonances and that transition probabilities can be described by two-photon generalized cross sections.

Contribution

It provides a detailed analysis of the resonant and nonresonant contributions to attosecond SERS and demonstrates the applicability of rate models and two-photon cross sections in this regime.

Findings

Continuum transitions dominate SERS over autoionizing resonances.

Rate models accurately predict SERS transition probabilities.

Two-photon generalized cross sections describe SERS in high-intensity EUV regimes.

Abstract

We have calculated the resonant and nonresonant contributions to attosecond impulsive stimulated electronic Raman scattering (SERS) in regions of autoionizing transitions. Comparison with Multiconfiguration Time-Dependent Hartree-Fock (MCTDHF) calculations find that attosecond SERS is dominated by continuum transitions and not autoionizing resonances. These results agree quantitatively with a rate equation that includes second-order Raman and first-and second-order photoionization rates. Such rate models can be extended to larger molecular systems. Our results indicate that attosecond SERS transition probabilities may be understood in terms of two-photon generalized cross sections even in the high-intensity limit for extreme ultraviolet wavelengths.