Local Structure of Bulk and Nanocrystalline Semiconductors Using Total Scattering Methods

Dynamic Stereochemical Activity of the Sn2+ Lone Pair in Perovskite CsSnBr3

“…This is indicative that the data cannot be explained by anisotropic ADPs alone; however, it must be recognized that this may be due to a limitation of PDFgui, which applies the harmonic approximation and thus generates Gaussian peak shapes. 63,64 Therefore, if a harmonic approximation is assumed, a two-peak model, such as that of a rhombohedrally-distorted local symmetry, may provide a better description of this peak within the limitations of the analysis.…”

Reactivity of Surface Species in Heterogeneous Catalysts Probed by In Situ X-ray Absorption Techniques

“…Basic considerations. Although known and used before the theory of EXAFS was firmly defined 670 by the work of Sayers, Stern, and Lytle 395 (see section 2.3.1), and although based on a different physical process, the total scattering technique, [655][656][657][658][659][660][661][662]671 able to provide the overall pair distribution function (PDF) G(r) of the material, requires a special paragraph. The experimental setup needed is that of X-ray or neutrons powder diffraction 672,673 (Figure 12a), but the scattering pattern has to be collected to much higher exchanged Q-values, up to at least 20−30 Å −1 .…”

Determination of the electronic and structural configuration of coordination compounds by synchrotron-radiation techniques

“…Indeed, independently from the ordering level of the investigated system, the same link between the reciprocal and the real space (and vice versa) still holds, that is: the scattering amplitude is the FT of the electron density [213]. The related techniques are commonly referred to as X-ray scattering (XRS) methods [145,146,469,470]. Indeed, a short-range ordered sample can be modelled as a statistical ensemble of randomly oriented sub-units, similarly to the micro-crystalline domains in a XRPD experiment.…”

“…In principle, all coherent scattering have to be acquired. In practice, data collection extended at least up to q-values such high as 20-30 Å -1 [143,146] is desirable to satisfactorily limit FT truncation errors. Nevertheless, the required r-space extension and resolution of the PDF should be evaluated case by case, also considering the intrinsic width of the PDF peaks due to thermal vibrations, to optimize the q-range to probe and determine the instrumental q-space resolution needed [516].…”

“…Coming to scattering techniques, it is evident that multi-wavelength anomalous dispersion (MAD) [136][137][138][139][140][141] has taken great advantage from the development of third generation synchrotron radiation facilities [142]. The same holds for total scattering studies [143][144][145][146], requiring high photon fluxes at very short wavelength values. The peculiarities of third generation synchrotrons and of free electron lasers (FELs) make time [147][148][149][150][151][152][153] and space [154][155][156] resolved experiments possible at different scales which lower limits are progressively improved year after year.…”