scholarly journals New methods in time-resolved Laue pump–probe crystallography at synchrotron sources

2015 ◽  
Vol 22 (2) ◽  
pp. 280-287 ◽  
Author(s):  
Philip Coppens ◽  
Bertrand Fournier

Newly developed methods for time-resolved studies using the polychromatic and in particular the pink-Laue technique, suitable for medium and small-size unit cells typical in chemical crystallography, are reviewed. The order of the sections follows that of a typical study, starting with a description of the pink-Laue technique, followed by the strategy of data collection for analysis with the RATIO method. Novel procedures are described for spot integration, orientation matrix determination for relatively sparse diffraction patterns, scaling of multi-crystal data sets, use of Fourier maps for initial assessment and analysis of results, and least-squares refinement of photo-induced structural and thermal changes. In the calculation of Fourier maps a ground-state structure model, typically based on monochromatic results, is employed as reference, and the laser-ON structure factors for the Fourier summations are obtained by multiplying the reference ground-state structure factors by the square root of the experimental ON/OFF ratios. A schematic of the procedure followed is included in the conclusion section.

2013 ◽  
Vol 117 (38) ◽  
pp. 11015-11021 ◽  
Author(s):  
Maria M. Mendes-Pinto ◽  
Elodie Sansiaume ◽  
Hideki Hashimoto ◽  
Andrew A. Pascal ◽  
Andrew Gall ◽  
...  

1999 ◽  
Vol 55 (10) ◽  
pp. 1733-1741 ◽  
Author(s):  
Dominique Bourgeois

Tools originally developed for the treatment of weak and/or spatially overlapped time-resolved Laue patterns were extended to improve the processing of difficult monochromatic data sets. The integration programPrOWallows deconvolution of spatially overlapped spots which are usually rejected by standard packages. By using dynamically adjusted profile-fitting areas, a carefully built library of reference spots and interpolation of reference profiles, this program also provides a more accurate evaluation of weak spots. In addition, by using Wilson statistics, it allows rejection of non-redundant strong outliers such as zingers, which otherwise may badly corrupt the data. A weighting method for optimizing structure-factor amplitude differences, based on Bayesian statistics and originally applied to low signal-to-noise ratio time-resolved Laue data, is also shown to significantly improve other types of subtle amplitude differences, such as anomalous differences.


2002 ◽  
Vol 17 (25) ◽  
pp. 3681-3688 ◽  
Author(s):  
LISA FREYHULT

We compute the effective potential of SU(2) Yang–Mills theory using the background field method and the Faddeev–Niemi decomposition of the gauge fields. In particular, we find that the potential will depend on the values of two scalar fields in the decomposition and that its structure will give rise to a symmetry breaking.


2012 ◽  
Vol 116 (47) ◽  
pp. 11651-11655 ◽  
Author(s):  
Xin Liu ◽  
Lin Li ◽  
Bo Liu ◽  
Dongqi Wang ◽  
Yuliang Zhao ◽  
...  

2020 ◽  
Vol 32 (7) ◽  
pp. 2824-2835 ◽  
Author(s):  
Adrien Perrichon ◽  
Erik Jedvik Granhed ◽  
Giovanni Romanelli ◽  
Andrea Piovano ◽  
Anders Lindman ◽  
...  

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