Real-space Green’s function approach to resonant inelastic x-ray scattering

Abstract

We present an ab initio theory of core and valence resonant inelastic x-ray scattering (RIXS) based on a real-space multiple scattering Green's function formalism and a quasi-boson model Hamiltonian. Simplifying assumptions are made which lead to an approximation of the RIXS spectrum in terms of a convolution of an effective x-ray absorption signal with the x-ray emission cross-section. Additional many body corrections are incorporated in terms of an effective energy dependent spectral function. Example calculations of RIXS are found to give qualitative agreement with experimental data. Our approach also yields simulations of lifetime-broadening suppressed XAS, as observed in high energy resolution fluorescence detection experiment (HERFD). Finally possible improvements to our approach are briefly discussed.

Photoinduced Structural Dynamics of Molecular Systems Mapped by Time-Resolved X-ray Methods

“…In addition, the transferred energy corresponds to elementary excitation of the final state of the material, which can include low-energy excitations such as charge-transfer or ligand-field excitations in the case of metal complexes. 145,146 …”

1s2p RIXS Calculations for 3d Transition Metal Ions in Octahedral Symmetry

“…The higher energy range of the final states is reached via the intermediate state probed by the quadrupole E g IRREP (1s XAS operator). [39]. Compared with the calculations in Figure 40, the intensity ratio of the T 2g and the E g peak is inverted in the experiment, with the E g peak at [6540,638] eV having the largest intensity.…”

“…Experimental 1s2p RIXS experiments have been published on TiO 2 by Glatzel et al [38] and Kas et al [39]. The 1s2p RIXS planes show the quadrupole pre-edges and the nonlocal peaks.…”

High energy resolution off-resonant X-ray spectroscopy

“…The authors express the absorption coefficient in terms of effective one particle Green's function corresponding to the intermediate and the final many-body states [109,110]. The Green's function is separated into two summands [111]: one associated with the absorbing atom (which is taken as the leading term) and another describing multiple scattering on the surrounding atoms (which is treated as a perturbation).…”