May 2015 issue
X-ray scattering images collected on timescales shorter than rotation diffusion times using a (partially) coherent beam result in a significant increase in information content in the scattered data. In this communication, an intuitive view of the nature of fluctuation scattering data and their properties is provided, the effect of such data on the derived structural models is highlighted, and generalizations of the Guinier and Porod laws that can ultimately be used to plan experiments and assess the quality of experimental data are presented.
Based on the observation of second harmonic generation (SHG), the solid state structure of a Zn(II) complex has been reinterpreted in terms of the non-centrosymmetric space group Cc, with residual polarity arising from unequal antiparallel packing. Temperature-dependent measurements showed that the highest SHG has been observed at 50 K and the lowest at 170 K.
A serial femtosecond crystallography based method has been proposed, which enables simultaneous X-ray phase identification and structure solution for multiphase polycrystalline samples. Test results from simulating calculations are encouraging.
The analysis, based on Hirshfeld surfaces, reveals which atoms are the preferred partners of halogens in crystal packing contacts.
Cocrystallization of cyclic imides with benzoic acid and some of its hydroxyl analogues resulted in cocrystals and eutectics in a mutually exclusive manner depending on the presence or absence and position of the hydroxyl group and consequent supramolecular effect for different combinations.
The useful experimental data range for solution small-angle scattering is assessed through the number of meaningful Shannon channels that can be determined from a given data set, and a robust algorithm is provided to determine this range automatically.
We have mimicked the 4%-energy-bandpass mode of the SwissFEL beam at a synchrotron facility, collected snapshots of randomly oriented multi-crystal samples, and developed a methodology to index and process such non-monochromatic data for materials science applications.
Hybrid and monolithic detectors for X-ray imaging are reviewed.