A two-state Markov noise process for lattice fluctuations and chemical exchange dynamics is used to derive a stochastic Liouville equation describing the evolution of the spin-density operator in nuclear magnetic resonance spectroscopy. Relaxation through lattice fluctuations and chemical exchange processes is incorporated into the theory at the same fundamental level, and the results are valid...

The involvement of chemical exchange in 2D IR heterodyne echo spectroscopy is characterized through the hydrogen-bond exchange between CH3OH and the CN of CH3CN. The exchange dynamics on the hydrogen-bond potential surfaces associated with different quantum states of the high-frequency CN stretching mode contributes to strong cross peaks between CN groups in two different chemical configuration...

Ion exchange resins are used in several chemical decontamination or cleaning processes and in nuclear industries for removal of radionuclides.1–5 Nowadays, ion exchange resins are not only used for separation but also as catalysts. In the past decade, inorganic ion exchange materials have emerged as an increasingly important replacement or complement to conventional organic ion exchange resins....

Chemical exchange saturation transfer (CEST) and spin-locking (SL) experiments were both able to probe the exchange process between protons of nonequivalent chemical environments. To compare the characteristics of the CEST and SL approaches in the study of chemical exchange effects, we performed CEST and SL experiments at varied pH and concentrated metabolite phantoms with exchangeable amide, a...

Incorporation of Li cations into MOFs by either of two methods, chemical reduction or cation exchange, significantly improves the CO2/CH4 selectivity. While the selectivity enhancement by the chemical reduction seems to come from favorable displacement of catenated frameworks, the selectivity improvement by the Li cation exchange comes from enhanced solid–gas interactions. 2010 Elsevier Inc. Al...

Peptides are flexible The experimental parameters measured in n.m.r. studies, such as nuclear Overhauser effects (NOEs), coupling constants and chemical shifts, are all time averaged [ 11. NOEs are averaged by any process occurring faster than the cross-relaxation rate [2], which is usually in the range 0.1-50 s-'. Coupling constants are averaged by processes that occur faster than the coupling...