X-ray emission spectroscopy
[1][2][3] XES is also sometimes referred to as X-ray Fluorescence (XRF) spectroscopy, and while the terms can be used interchangeably, XES more often describes high energy resolution techniques [4] while XRF studies a wider energy range at lower resolution.
[8] Their work demonstrated that the electron beams produce artifacts, thus motivating the use of X-ray photons for creating the core hole.
While these early studies provided fundamental insights into the electronic configuration of small molecules, XES only came into broader use with the availability of high-intensity X-ray beams at synchrotron radiation facilities, which enabled the measurement of (chemically) dilute samples.
(X-ray diffraction) For this purpose, "perfect crystals" have been produced in many shapes, depending on the geometry and energy range of the instrument.
When the signal intensity is maximized, the photons diffracted by the crystal hit the detector in the Rowland plane.
The instrument's horizontal plane will now have a slight offset, which can be corrected by increasing or decreasing the detector angle.
In the Von Hamos geometry, a cylindrically bent crystal disperses the radiation along its flat surface's plane and focuses it along its axis of curvature onto a line-like feature.
The spatially distributed signal is recorded with a position-sensitive detector at the crystal's focusing axis, providing the overall spectrum.
Alternative wavelength dispersive concepts have been proposed and implemented based on Johansson geometry, having the source positioned inside the Rowland circle.
In contrast, an instrument based on Johann geometry has its source placed on the Rowland circle.
For this purpose, normal X-ray tubes with highly pure tungsten, molybdenum, palladium, etc., are made.
-line spectra find importance, as the relation between these lines and the electronic structure of the ionized atom becomes more detailed.
If we include the chemical compounds of 3d-transition metals, which can either be high-spin or low-spin, we get 2 mechanisms for each spin configuration.
-mainlines as seen in figure one and two, while the structural configuration of electrons within the compound causes different intensities, broadening, tailing and piloting of the
Yet, the experiment setup is quite complex and needs exact and fine-tuned crystal monochromators to diffract the tangential beam coming from the electron storage ring.
The spectrum produced from the combined data shows a clear advantage in that background radiation is almost completely eliminated while still having a highly resolute view of features on a given absorption edge (Fig.
In the field of development of new catalysts for more efficient energy storage, production and usage in the form of hydrogen fuel cells and new battery materials, the research of the
The exact shape of specific oxidation states of metals is mostly known, yet newly produced chemical compounds with the potential to become a reasonable catalyst for electrolysis, for example, are measured daily.
Several countries encourage many different facilities all over the globe in this unique field of science in the hope of clean, responsible and cheap energy.
[13] Soft X-ray emission spectroscopy (SXES) is an experimental technique for determining the electronic structure of materials.
X-ray emission spectroscopy (XES) probes the partially occupied density of a material's electronic states.
XES is element-specific and site-specific, making it a powerful tool for determining detailed electronic properties of materials.
Non-resonant excitation occurs when the incoming radiation promotes a core electron to the continuum.
Because the core hole is refilled from the sample's high-energy free states, the decay and emission processes must be treated separately dipole transitions.
Soft X-rays have different optical properties than visible light, and therefore, experiments must take place in ultra high vacuum, where the photon beam is manipulated using special mirrors and diffraction gratings.
Diffraction gratings are also used in the spectrometer to analyze the photon energy of the radiation emitted by the sample.
