X-Ray Diffraction Studies of Ionic Liquids: From Spectra to Structure and Back

Choline-amino acid ionic liquids: past and recent achievements about the structure and properties of these really “green” chemicals

“…Therefore, the whole spectrum of scattered wave vectors can be obtained either by varying the angle and keeping the radiation energy fixed (angular dispersive, ADXD, that uses a monochromatized beam) or by using a variable-wavelength energy beam (i.e., the Bwhite^part o f t h e r a d i a t i o n e m i t t e d b y a n X -R a y t u b e -Bremsstrahlung) and using a single angle or a limited number of angles (3 to 4). Several reviews on EDXD theory (Rossi and Caminiti 1999) and applications (Gontrani et al 2014;Caminiti et al 1997;Caminiti et al 1999), to which the reader is referred to, were published in the past. After data treatment (see Gontrani et al 2014) that normalizes the measured scattered intensity for absorption and subtracts self-scattering and the inelastic Compton scattering, the total coherent structure function, which is also known as Breduced intensity^, I(q), is obtained.…”

“…Several reviews on EDXD theory (Rossi and Caminiti 1999) and applications (Gontrani et al 2014;Caminiti et al 1997;Caminiti et al 1999), to which the reader is referred to, were published in the past. After data treatment (see Gontrani et al 2014) that normalizes the measured scattered intensity for absorption and subtracts self-scattering and the inelastic Compton scattering, the total coherent structure function, which is also known as Breduced intensity^, I(q), is obtained. I(q) is the structural sensitive part of the recorded diffracted intensity, as it depends on the sum of the interference contributions of the waves scattered by the atoms of the sample, and, ultimately, on their relative distances, as the atoms, through their electrons, are the particles taking part to the scattering phenomenon (scatterers).…”

New Insights into the Structure of Glycols and Derivatives: A Comparative X-Ray Diffraction, Raman and Molecular Dynamics Study of Ethane-1,2-Diol, 2-Methoxyethan-1-ol and 1,2-Dimethoxy Ethane

“…Several papers on EDXD theory [20,21] and applications [22][23][24][25], to which the reader is referred to, were published in the past. From the Fourier transform of I(q), the total radial distribution function of the sample is obtained.…”

The Opposite Effect of Water and N-Methyl-2-Pyrrolidone Cosolvents on the Nanostructural Organization of Ethylammonium Butanoate Ionic Liquid: A Small- and Wide-Angle X-Ray Scattering and Molecular Dynamics Simulations Study

“…Summarizing, the analysis of both reciprocal space ( QI ( Q ) M ( Q )) and distance space (Diff­( r )) functions is used to compare X-ray experimental data and simulations. This methodology has been successfully applied to the study , of molecular and ionic liquids, , as well as solutions. , For the comparative studies of the mixtures at low Q , the normalized structure function S ( Q ) functions will also be used (see below).…”

“…When systems of different composition are considered, the best way of comparing simulated X-ray patterns is through the normalized structure function: , since in this formulation the intensity is normalized by the number concentrations x i and the scattering power of the species f i ; − otherwise, the use of I ( Q ) (eq ) would give very different intensities for systems differing by the total number of electrons. The S ( Q ) functions calculated from MD trajectories are reported in Figure for both systems, and show that the experimental data of Figure can be reproduced well, apart from the relative heights of the peaks as just mentioned.…”