Chemical Analyses

One key method for structural analyses are diffraction methods. Therefore, X-rays are the probe used in-house as well as complemented by neutrons and more brilliant synchrotron X-ray beams as probes in large research facilities.

X-ray Bragg powder diffraction – Available is a copper X-ray diffractometer in Debye-Scherrer geometry, however, most everyday powder diffraction tasks are met by a powder diffractometer utilizing a molybdenum X-ray anode. While most samples are measured inert in capillaries, flat samples are used for highly absorbing or low Z samples. Measuring in capillaries allows temperature dependent diffraction to liquid nitrogen temperatures and a reaction furnace allows high-temperature diffraction and reaction monitoring with X-rays. The silver anode side of the same instrument allows for Bragg data collection but is optimized for their transformation for pair distribution function.

X-ray powder total scattering – As stated a silver X-ray anode-based powder diffractometer optimized for high flux and high Q-range for use of pair distribution function analyses is available. High and low temperature sample environment setups are compatible and available. Energy sensitive detectors allow for reduction in X-ray fluorescence.

Instrument specifications:

	Mo X-ray anode	Ag X-ray anode	Cu X-ray anode
Wavelength (energy)	0.7093 Å (~17.5 keV)	0.5594 Å (~22.2 keV)	1.5406 (~8.1) keV
2θ (equiv. Q-range) range	0° up to 125° (15.7 Å−1)	0° up to 135° (20.8 Å−1)	0° up to 125° (7.2 Å−1)
Angular step resolution	0.015°	0.015°	0.015°
Geometry/Sample type	Flat sample / Capillary	Capillary	Flat sample / Capillary
Detectors	2x Si Strip 2K	4x Si Strip 4K	1x Si Strip 1K
Sample enviroments			@ RT
Cryo-blower	−160 to +100 °C RT to –1600°C	−160 to +100 °C RT to –1600°C
High T reaction chamber	0.01 and 0.1 l/min gas flow	0.01 and 0.1 l/min gas flow

Raman Microscope – A Raman microscope is available with a “green Laser” @532 nm allowing visual sample inspection, digital microscopy and microscopy aided Raman spectroscopy of samples with inert sample transfer established.

Instrument specifications:

Microscopy	10x, 20x, 50x
Video FoV	300 x 250 µm (20x),130 x 100 µm (50x)
Stage	Motorized x, y, z ±0.1 µm (autofocus)
Raman spectroscopy	@ 20x, 50x
Wavelength	532 nm
Wavenumber range	50 – 4200 cm−1 (Stokes)
Resolution	4 cm−1 & 1.5 cm−1
Laser Power	0.25 – 25 mW
Spatial resolution	<0.5 µm
Confocal depth resolution	2 µm
Temperature	Ambient

X-ray Photoelectron spectroscopy – Chemical analyses at surfaces can be performed using electron spectroscopy of X-ray photoelectrons.

Interested? – Feel free to request collaborative measurements or instrument access to marvin.kraft@uni-muenster.de or ptill@uni-muenster.de.