Coherent two-dimensional electronic-x-ray spectroscopy

Le résumé fourni par la source

Ultrafast pump-probe time resolved x-ray spectroscopy carries information on the valence-core dynamics of molecular systems. Here, a coherent two-dimensional nonlinear electronic-x-ray spectroscopy (2DEX) application is proposed in order to reveal the frequency-frequency correlations for the valence and the core transition excitations. 2DEX is in the class of extreme-cross peak correlation spectroscopy and is experimentally straightforward to measure as an adaptation of the conventional optical pump-x-ray probe technique by creating a phase-locked pulse pair of the ultrafast laser for the valence excitation. Theoretical evaluation of the coherences and populations for several applications of ultrafast valence-core spectroscopy experiments is shown. Using a response function approach, 2DEX, four wave signals are calculated and evaluated with respect to frequency separation in the electronic and x-ray ranges as well as the line shape characteristics. It is shown that stationary and oscillatory contributions to the rephasing, non-rephasing, and absorptive signals can be resolved depending on pulse shaping and phase cycling, phase matching, x-ray spectrometer, and material response parameters. Calculations are shown for examples that include the valence-core coherences for a vibrational monomer and for Frenkel and charge transfer electronic exciton states, which in the x-ray absorption near-edge structure spectral region has the potential to resolve the population and coherence contributions in the atomic localized basis.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.