Identification of different crystalline phases and the determination of their relative concentrations in mixtures based on the diffraction pattern analysis recorded from the powder samples: precise determination of the unit cell parameters of the known substance to detect isomorphic impurities, indexing of diffraction patterns, and determination of unit cell parameters and possible space group for new compounds.
The main task of the single-crystal X-ray analysis is to determine the crystal structure, namely the determination of symmetry, unit cell parameters, atoms coordinates, atoms displacement parameters, bond lengths and angles between the atoms, topology of a structure. During the structure determination process it is possible to refine such crystallographic characteristics as ordering / disordering of cations (anions), site occupancy factor, analysis of superstructures.
Method allows determination of the phase transition temperature and most trustable interpretation of various phase transition, particularly: solid state transformations (polymorphism, decomposition, new phase formation, amorphisation etc.), melting processes (congruent, eutectic, peritectic etc.), dehydration and others. For the specific tasks experiment can be performed in different atmospheres: air, vacuum, nitrogen, inert gas. Powder substance under study should be placed on a metal sample holder (Cu for low- and Pt for high-temperatures) into a high/low temperature camera, attached to a diffractometer. Heating is carried out using a resistance furnace allowing accurate achievement of high temperatures with relatively low temperature gradients. Cooling in the low temperature camera is performed using liquid nitrogen in vacuum. XRD patterns could be taken with a temperature step or using continuous heating mode.
Studies of surfaces and interfaces between substrates and thin epitaxial layers in both simple and complex multilayer systems. Determination of layer thickness and interface roughness, lattice mismatch and relaxation, composition of solid solution, crystallinity, mosaicity and strain, dislocation density and precise lattice constant measurement. Non-destructive control of bulky industrial single crystals produced for electronics and optical devices. Study of residual stress and textures in ceramic and metallic samples. Microstructural analysis ("size and starin") in both bulky samples and tiny catalyst nanoparticles.
Spectroscopy and thermal analysis techniques, such as UV-VIS, FTIR, DSC, TGA, are complementary to X-ray diffraction phase and structure analysis, expanding possibilities for correct crystal structure solution and refinement, along with correct determination of phase compositions for complex mixtures.
Picarro is WS-CRDS (wavelength-scanned cavity ring down spectroscopy) – based isotope analyzer.
Equipment: Microtomography scanner SkyScan 1172 or nanotomography scanner SkyScan 2011
