Structure and Dynamics of Solutions Studied by X‐Ray and Neutron Scattering

Abstract

X‐ray and neutron scattering techniques give us direct information of the microscopic structure (interatomic distance and coordination number) and dynamic properties (vibrational, translational, and rotational motions) of ions and solvents in solutions. Firstly, theoretical background in X‐ray and neutron scattering and empirical potential structure refinement modeling is described, followed by instrumentation of laboratory‐scale and synchrotron radiation X‐ray sources and pulsed neutron sources. Coherent X‐ray and neutron scattering methods of solutions are exemplified for the microscopic structure determination of ion solvation and solutions under pressure. Inelastic X‐ray and neutron scattering methods, such as quasi‐elastic neutron scattering and neutron spin‐echo methods, are described in theory and instrumentation. The dynamic properties of supercritical methanol and water confined in mesoporous materials are described. Finally, conclusions and perspectives are represented.

Characterization of the Coordination and Solvation Dynamics of Solvated Systems─Implications for the Analysis of Molecular Interactions in Solutions and Pure H2O

“…The significance of solvation in the reactivity of chemical species such as atoms, ions, and molecules in solution is widely recognized. – The exchange of solvent molecules from the primary solvation layer can be considered as an initial step in enabling chemical reactions and complex formation. , The different properties of solvation structures and the associated kinetics of solvent exchange have been extensively investigated by using both experimental as well as theoretical approaches. Experimentally, techniques such as X-ray/neutron diffraction and scattering – as well as extended X-ray absorption fine structure and X-ray absorption near edge structure spectroscopy – are typically employed to study the coordination of dissolved ions and molecules by solvent molecules. To characterize the dynamics of solvent exchange, nuclear magnetic resonance , and incoherent quasi-elastic neutron scattering – have been employed.…”

“… 5 , 6 The different properties of solvation structures and the associated kinetics of solvent exchange have been extensively investigated by using both experimental as well as theoretical approaches. Experimentally, techniques such as X-ray/neutron diffraction and scattering 7 – 11 as well as extended X-ray absorption fine structure and X-ray absorption near edge structure spectroscopy 12 – 14 are typically employed to study the coordination of dissolved ions and molecules by solvent molecules. To characterize the dynamics of solvent exchange, nuclear magnetic resonance 5 , 10 and incoherent quasi-elastic neutron scattering 15 – 19 have been employed.…”