meV-RIXS

What can you do with the new beamline?

The M-edges of transition metals, the N-edges of rare earths, and the L-edges of silicon, phosphorus, and sulphur will be accessible with the meV-RIXS setup at the UE112-PGM1. The world’s highest resolution of a few meV over the range of 30–200 eV allows the study of scientifically important mixed-valence functional materials, as well as photo and electrochemical entities.

What is new about it?

meV-RIXS at BESSY II accesses for the first time the parameter space of single meV resolution over the previously unexplored spectral region of 30–200 eV. meV-RIXS is fully complementary in its energy range and resolution to other state-of-the-art high-resolution RIXS spectrometers in the energy range of 300–2,000 eV and bandwidth of 10–100 meV.

What is the goal?

The objective of the meV-RIXS project is to establish low-energy RIXS methods as well as to perform complementary studies of the high valence states for transition metals and rare earth elements in the previously unexplored spectral region of 30–200 eV.

About the project

The functionality, chemical selectivity, and reaction speed of materials are determined by the coupling of low-energy excitations of spin, orbital, and lattice degrees of freedom. meV-RIXS opens up a new approach by bringing the outstanding selectivity of RIXS with respect to elemental composition, chemical state, orbital polarisation, and electronic and magnetic excitations to the energy region of a few meV.

It therefore closes a gap in the performance between conventional q-resolved RIXS measurements in the keV region with a spectral bandwidth between 10–100 meV and inelastic neutron scattering (INS). While the latter method attains sub-meV resolution with spin selectivity, it is requires large sample volumes and does not provide elemental, chemical, or orbital selectivity.

With this new setup, we will achieve world-leading resolution of a few meV at the M-edges of transition metals, the N-edges of the rare earths, the L-edges of silicon, phosphorus, sulphur, and chlorine as well as the K-edges of carbon and boron. Scientifically important mixed-valence functional materials, photochemical and electrochemical entities, as well as organic materials will become accessible at an energy scale of a few meV in combination with the unique selectivity of RIXS with regard to elemental composition, chemical state, orbital polarisation, and magnetic excitations.

Spectrometer resolution

Transmission and resolving power E/dE for the 1,050 l/mm grating of the meV-RIXS spectrometer.