- Physical and Non-Physical Methods of Solving Crystal Structures | Marek Lewinson
- Tan Kah Kee Science Award in Mathematics & Physicis 2006
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Mode of access: World Wide Web. X-ray crystallography Technique. X-ray crystallography Techniques. Fan, Hai-fu. Cambridge University Press. Related item. Bibliography Electronic books. Illustrated text. Internet Resources. Back to results. University of Birmingham Libraries.
University of Bristol Libraries. Altmetric -. Citations Cited By. This article is cited by 49 publications. DOI: Manal A. Khoj, Colan E. Hughes, Kenneth D. Harris, and Benson M. Hughes, Duncan L. Browne, Thomas R. Peskett, and Kenneth D. Kilingaru I. Shivakumar, Yuncheng Yan, Colan E. Hughes, David C. Apperley, Kenneth D. Harris, and Gangadhar J. Andrew Williams, Colan. Hughes, Asma B. Buanz, Simon Gaisford, and Kenneth D. The Journal of Physical Chemistry C , 23 , Harris, David C. Apperley, Peter N.
Horton, Michael B. Hursthouse, and Stuart L. Andrew Williams, Colan E. Kariuki, and Kenneth D. Harris, and David C. Eugene Y. Harris, Sayoko Hasebe, and Reiko Kuroda. Kitchin, Benson M.
Physical and Non-Physical Methods of Solving Crystal Structures | Marek Lewinson
Kariuki, Douglas Philp and Kenneth D. Kariuki and Kenneth D.
Elizabeth J. Kariuki, James R. Cameron, Mark A. Roberts and Kenneth D. Harris and, Eugene Y. Kenneth D. Kariuki, and, Kenneth D.
The Journal of Physical Chemistry B , 44 , Harris, , Maryjane Tremayne. Chemistry of Materials , 8 11 , Harris, Benson M.
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Polymorphic phase transformations of 3-chloro- trans -cinnamic acid and its solid solution with 3-bromo- trans -cinnamic acid. Conformational and characterization of benidipine hydrochloride polymorphs: Spectroscopic and computational modeling investigations. Journal of Molecular Structure , , Many reproducible copies will need to be measured to get a sufficient signal to noise ratio for each projection necessary for three-dimensional 3D imaging at sub-nanometer spatial resolution. Free-electron lasers are especially well suited for such coherent 2D crystallography.
They provide femtosecond coherent pulses with extremely high power.
Tan Kah Kee Science Award in Mathematics & Physicis 2006
Only the combination of all of these unique properties will allow the realization of 2D crystallographic x-ray imaging on biological systems. Brilliant, ultrashort pulses could overcome the radiation damage problem [ 3 ] which is a severe limitation of conventional crystallography at 3 rd generation synchrotron sources [ 4 ]. Higher luminosity and hence improved statistics for such experiments can be obtained by the use of pulse trains that can be provided by FLASH [ 5 ]. We demonstrate finite crystallography by using a micro-structured crystal array that was prepared on a nm thick silicon nitride membrane substrate coated with nm of gold, and nm of palladium.
The finite crystal sample was manufactured by milling holes in the film in a regular array pattern using a Focused Ion Beam FIB. The 'unit cell' of our crystal consists of a large hole of nm diameter representing a 'heavy atom' in conventional crystallography and a smaller hole of nm diameter representing a 'light atom'. The scheme of experiment is shown in Fig.
We used a 0.
This is an order of magnitude higher than the expected coherent flux of about 3x10 9 photons on the same sample area for the same exposure time at a 3 rd generation synchrotron source. A typical data set is shown in Fig. The diffraction pattern as measured contains signal up to the edge of the detector, which corresponds to a minimum feature size of nm Fig.
We note that all expected features of a finite, crystalline structure are observed. The Bragg peaks due to the regular array are clearly seen, as are the oscillations between the Bragg peaks that are the result of the finite extent and coherent illumination of our sample. Also seen is the form factor from the individual elements — the large holes — that can be observed as a radial intensity modulation across the pattern produced.
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The preprocessed data set shown in Fig. A scanning ion micrograph SIM image of the object under investigation is shown in Fig. The initial square support used for reconstruction is indicated by a dashed line in Fig. It is very clearly seen in Fig. Note also the diffuse, elongated background present in the reconstruction. Our analysis have shown that one of the reasons for the limited resolution and its sensitivity to noise obtained in our initial reconstructions is due to the fact that the measured diffraction pattern has two equivalent, symmetric solutions.
One is with the small dots appearing to the top right of the larger dots, and the other is with them appearing to the bottom left. Due to this symmetry the reconstruction algorithm does not fully converge, but rather stagnates with two equivalent solutions superimposed with each other. To solve this problem we have binned the data 5x5 yielding a sampling rate of 6 in each dimension. In addition, instead of using a large square support we use a more constrained support of 25 rectangular boxes each centered on the positions of the unit cell see Fig.
By improving the signal-to-noise ratio and reducing the symmetry in real space we were able to improve the reconstruction to the level that we resolved the smallest features present in our sample Fig.