Located in the Department of Chemistry & Biochemistry room 4608 PSB-N, the X-ray lab has the
instrumentation to perform small-molecule single-crystal and
powder-diffraction experiments. X-ray diffraction is a
nondestructive technique widely used in physics, chemistry,
biology and materials science to characterize the structures and
properties of solid state materials. Single-crystal
diffraction can provide precise information about 3-D molecular and
crystal structures, while powder diffraction is mainly
used in qualitative and quantitative phase analysis, the
characterization of various properties such as particle size,
strain, and stress of polycrystalline samples.
The PC-controlled, fully automated instruments come with
well-developed analytical software packages giving users the
capability for comprehensive solutions from the acquired
data. The facilities provide access for both on-campus and
off-campus users. Lab users can either conduct the experiments
themselves after operation and safety training or submit the
samples to lab staff who will provide the service of data
collection and processing. To
schedule an experiment, users
should contact the lab staff. Periodically, the X-ray lab staff
organizes group training in instrument operation and data
analysis. Individual training is also available upon request.
Kappa Apex II Diffractometer
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- Chemical Crystallography
The new Kappa Apex II single-crystal diffraction system integrates the most sensitive and fastest CCD detector and Mo fine focus sealed tube with TRIUMPH monochromator. This combination can provide very fast and precise data collection and structure determination. It can collect decent diffraction intensity data from crystal having size as small as 20 microns. The system is also equipped with Oxford Cryostream-Plus, which can perform temperature-dependent measurement from 80K to 500K. The 4-axis diffractometer allows identification of crystal faces, oriented X-ray scan and other analyses. This instrument is supported by the National Science Foundation under CHE-1040541
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Proteum Diffractometer
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- Biological Crystallography
The Proteum diffraction system combines a Microstart Cu rotating anode and 3-axis platform diffractometer. The generator has 2.7 kW anode power loading on a 100 µm focal spot. Together with the multi-layer optics, it can provides ultra-high intensity: up to 8 x 1010 X-rays/mm2 –sec. The system is equipped with an Oxford 700 cryostream. It is ready for data collection from protein crystals or other biological samples. It also can be used collect data from organic and inorganic crystals which have micron size or large unit cell, and for chirality determination of organic molecules in absence of heavy atoms.
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2-D Powder X-ray Diffraction
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- 2-D X-Ray Diffraction and Scattering
Both systems can perform fast 2D diffraction or scattering from very small amounts of powder or fiber samples to study phase identification, crystallinity, texture and other chemical and physical properties. The associated software package can perform data processing calculations and export the files in formats compatible with other commonly used software.
With the cryostream, fast in-situ temperature dependent diffraction measurements can be taken.
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| Structure determination provides a vivid atomic connectivity and 3D molecular conformation and reveals the inter-molecular interaction and packing. |
The indicies of crystal faces can be identified based on the orientation matrix. The diffractometer can rotate the defined face along a reference direction for visual observation or X-ray scan. |
The oriented X-ray scan can help to observe defects, superlattice and other crystal properties. |
Powder Diffraction
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- Diffractometer: Scintag X2
θ-θ diffractometer
- X-ray Source and Optics: Sealed 2kW Cu tube,
manually adjustable slits for incident and diffracted beam
- Detector: Solid state point detector
- Software: Windows version Scintag data collection
and analysis package, ICDD PDF database
- Sample Requirement: Powder, thin film
- Application: Phase identfication, high resolution data for structure refinememt
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Lab Manager: Dr. Guang Wu
Office: 4610 Physical Sciences Building North
Phone: (805) 893-2399
Email:
wu@chem.ucsb.edu
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