- Physical Sciences
Dr. Aitor Larrañaga Varga Phone: 94 601 2599 e-mail: aitor.larranaga@ehu.es Dr Leire San Felices Mateos Phone: 94 601 3488 e-mail: leire.sanfelices@ehu.es
The X-ray Service may used by researchers from University Colleges, Technology Centres and Companies, etc. Routine and special experiments can be carried out, in addition to analyses of results. The Service Personnel can in any event advise you about the most suitable experiments and conditions for each problem. Access to the unit of X-rays: Molecules and Materials involves meeting the requirements set forth in the Protocol for access to SGIker and the services it provides.
The General X-ray Service of the University of the Basque Country/EHU attempts to provide support for basic and applied research in, among others, the different areas of knowledge of Geological Science, Chemistry, Materials Science, Aeronautics, Pharmacy, Biochemistry, Archaeology, Palaeontology, Anthropology and Environmental Science, in addition to helping to provide a service in the fields of Construction, Mining Prospecting and Civil Engineering. Researchers may also access the service from the Basque Network of Science and Technology, and it is available to other researchers outside the UPV/EHU, and other public and private institutions - both national and international. Integrated in the General Service of X-ray Analysis, the Unit Molecules and Materials, provides the structural study of organic and inorganic materials in the form of single crystals or polycrystalline sample, under a wide range of conditions. The performance of this unit covers all aspects of the study of crystal structure from diffraction data: the selection and installation of the sample, previous studies of symmetry, diffraction data collection, the resolution or structural identification and the analysis of results. The available equipment also enables structural studies starting from diffraction data of polycrystalline materials. This technique allows us to identify the crystalline phases present in the sample without destroying it, allowing you to recover the material without deterioration. It is possible to characterize, in a wide variety of materials, his crystalline structure, or the presence of texturin or residual stresses, material fatigue, etc., These studies were performed by analyzing the profile of diffractogram using, in the cases that require it, the Rietveld method. The X-Ray Service: Molecules and Materials Unit supports basic and applied research through scientific and technical advice and the use of a high-performance infrastructure in materials analysis by X-ray diffraction, with applications in many areas knowledge.
Monocrystal sample: - Visual selection and preparation (assembly) of the crystal. The samples are accepted as previously filtered crystals or in solution, with the latter being the preferable option in many cases. - Prior quality measures and preliminary data-taking, the moment when the monocrystal to be measured is selected, the unit cell parameters are determined, along with its symmetry (preliminary). When necessary, the ICSD and CSD crystallographic data bases are consulted with this information to determine whether the crystalline phase in question has already been determined and published in international data bases. If that is not the case, the preliminary data taking allows the most appropriate diffractometer to be selected and the measurement conditions be optimized: temperature, angular range, time,… - Diffraction data collection. The data taking is performed at 100K by default, except in those cases when the user requests the contrary, or the preliminary data indicate the formation of an intersecting twin, non-desired phase transition, crystal degradation or any other non-desired effect when the temperature is reduced. In any case, the data taking can be performed at a wide range of temperatures (10-600K) and can be performed at different temperatures for phase transition studies. - Data processing. The process can end here if the user has sufficient knowledge to solve and refine the structure. - Structural resolution, tuning and results presentation (report). The results obtained are sent to the users in the form of reports, graphs and/or tables, always facilitating the source data collected by the diffractometer, along with information relating to the equipment user,measurement conditions, etc. A comprehensive CIF file, ready to be entered in the database and/or for publication, is delivered. Polycrystalline Sample: - Diffractogram measuring and processing: the specific diffractometer software is used to prepare the measurement programs as per the needs raised by the users. - Phase identification: the phases are identified using specific software, combined with the ICDD PDF2-4 database, for the users that so require this service. - Data processing for crystallinity analysis, crystalline domain size and efforts. The data processing is performed both at the level of individual diffraction maxims and by means of full diffraction diagram processing. - Quantitative analysis: by means of the theoretical simulation of the diffraction diagrams using full profile tuning with structural model both of pure phases and for compound mixtures. This methodology requires a complex and intense data processing task, along with the registration of X-ray diffraction diagrams in high-resolution polycrystalline sample. - Data presentation: the results obtained are sent to the users in the form of reports, graphs and/or tables, always facilitating the source data collected by the diffractometer. The users are also given information on the equipment users, measurement conditions, methodology followed to prepare samples, etc. - Training by means of specific courses. Educational support for various degrees and Master’s degrees.
University of the Basque Country UPV/EHU Science and technology faculty Edificio CD3 Bº Sarriena, s/n 48940 Leioa (Bizkaia)
