Quadrupolar Nuclei in Solids

Vega, Alexander J.

doi:10.1002/9780470034590.emrstm0431.pub2

Cited by 27 publications

(35 citation statements)

References 60 publications

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“…Nuclear magnetic resonance (NMR) spectroscopy has long been heralded as a sensitive probe of the local environment in solids, able to provide detailed information on structure and disorder in the solid state, while its sensitivity to motion over a wide range of timescales also enables dynamics to be investigated. 1,2 The use of 1 H, 13 C, 29 Si and 31 P NMR spectroscopy has had a significant impact in the pharmaceutical industry, materials chemistry, geochemistry and industrial chemistry, for the study of drugs and active pharmaceuticals, catalysts, glasses, zeolites and minerals. [3][4][5][6][7][8][9][10] Unlike their solution-state counterparts, NMR spectra of solids are affected by anisotropic, or orientation-dependent interactions, including the chemical shift anisotropy (CSA) and the dipolar coupling, preventing the extraction of site-specific information.…”

Section: Introductionmentioning

confidence: 99%

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New Methods and Applications in Solid-State NMR Spectroscopy of Quadrupolar Nuclei

2014

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Solid-state nuclear magnetic resonance (NMR) spectroscopy has long been established as offering unique atomic-scale and element-specific insight into the structure, disorder, and dynamics of materials. NMR spectra of quadrupolar nuclei (I > (1)/2) are often perceived as being challenging to acquire and to interpret because of the presence of anisotropic broadening arising from the interaction of the electric field gradient and the nuclear electric quadrupole moment, which broadens the spectral lines, often over several megahertz. Despite the vast amount of information contained in the spectral line shapes, the problems with sensitivity and resolution have, until very recently, limited the application of NMR spectroscopy of quadrupolar nuclei in the solid state. In this Perspective, we provide a brief overview of the quadrupolar interaction, describe some of the basic experimental approaches used for acquiring high-resolution NMR spectra, and discuss the information that these spectra can provide. We then describe some interesting recent examples to showcase some of the more exciting and challenging new applications of NMR spectra of quadrupolar nuclei in the fields of energy materials, microporous materials, Earth sciences, and biomaterials. Finally, we consider the possible directions that this highly informative technique may take in the future.

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Section: Introductionmentioning

confidence: 99%

“…The NMR spectra of quadrupolar nuclei, i.e., those with I > 1/2, are additionally affected by an interaction with the electric field gradient at the nucleus. 13,14 The anisotropic quadrupolar broadening can be significant, with lineshapes broadened over many MHz.…”

Section: Introductionmentioning

confidence: 99%

New Methods and Applications in Solid-State NMR Spectroscopy of Quadrupolar Nuclei

2014

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“…The dynamics of electron and nuclear spins is utilized in the wide area of magnetic resonance‐based techniques, including spectroscopy, imaging and microscopy, such as electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR) spectroscopy, magnetic resonance imaging (MRI), and magnetic resonance force microscopy (MRFM) . However, the dynamics of the electron and nuclear spins is governed by their complex interactions with other spins and with their surroundings, including external magnetic fields, both static and oscillating.…”

Section: Introductionmentioning

confidence: 99%

Introduction to average Hamiltonian theory. I. Basics

Brinkmann

2016

Concepts Magnetic Resonance

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Understanding the dynamics of electron or nuclear spins during a magnetic resonance experiment requires to solve the Schr€ odinger equation for the spin system considering all contributions to the Hamiltonian from interactions of the spins with each other and their surroundings. In general, this is a difficult task as these interaction terms can be both time-dependent and might not commute with each other. A powerful tool to analytically approximate the time evolution is average Hamiltonian theory, in which a time-independent effective Hamiltonian is taking the place of the time-dependent Hamiltonian. The effective Hamiltonian is subjected to the Magnus expansion, allowing to calculate the effective Hamiltonian to a certain order. The goal of this paper is to introduce average Hamiltonian theory in a rigorous but educational manner. The application to two composite pulses in NMR spectroscopy is used to demonstrate important aspects of average Hamiltonian theory. K E Y W O R D S average Hamiltonian, average Hamiltonian theory, composite pulse, effective Hamiltonian, Magnus expansion

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“…The pure quadrupolar relaxation of half integer nuclei in and out of the motionally narrowed regime has been thoroughly discussed in the literature. [37][38][39][40][41][42][43][44][45][46][47][48][49][50] The exact relaxation theory of quadrupolar nuclei being beyond the scope of this article, we restrict to remind some salient points when calculating the relaxation times for 3/2 nuclei.…”

Section: Theoretical Background For Calculation Of Longitudinal Andmentioning

confidence: 99%

“…48 The T 2 relaxation also reveals two decay components out of extreme narrowing condition which are directly related to the central and satellite transitions 43,44 and with a passage through a minimum when s c~x0 À1 for the central transition component. 44,46 Importantly, for correlation times longer than 10 À9 s, very large line-widths of satellite transitions will push them beyond detectability, whereas the decay of the central transition coherence occurs on the time scale of the longitudinal magnetization. The plots in Figure 3 also reveal that for a given correlation time s c and for cross-links with different site symmetry or motional amplitude resulting in different residual quadrupolar coupling, higher quadrupolar couplings generate larger linewidths manifesting themselves by increasing losses of the height of relevant resonance signals from the central transition.…”

Section: Probing T 1 and T 2 Quadrupolar Relaxation Times Of Sulfurmentioning

confidence: 99%

Toward recording ³³S NMR spectra of cross‐linked elastomers: Relaxation dynamics perspective

Marhabaie

Tékély

2016

Concepts Magnetic Resonance

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We discuss from the perspective of relaxation dynamics the feasibility of recording NMR spectra of 33S nuclei bound to cross‐link junctions in cross‐linked elastomers (i.e. vulcanized rubber). Assuming the quadrupolar relaxation mechanism due to fluctuating electric field gradients, the calculations of transverse and longitudinal 33S relaxation times encompassing a large range of correlation times, static magnetic fields, and quadrupolar coupling constants reveal that both relaxation processes will constitute significant bottlenecks in recording the 33S spectra of cross‐linked elastomers inherently endowed with a large distribution of motional modes. In the rubbery state, the observable 33S NMR signal will result from motionally averaged, central transition magnetization of the 33S nuclei in cross‐link junctions involved in large amplitude, high‐frequency motions.

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Quadrupolar Nuclei in Solids

Cited by 27 publications

References 60 publications

New Methods and Applications in Solid-State NMR Spectroscopy of Quadrupolar Nuclei

New Methods and Applications in Solid-State NMR Spectroscopy of Quadrupolar Nuclei

Introduction to average Hamiltonian theory. I. Basics

Toward recording ³³S NMR spectra of cross‐linked elastomers: Relaxation dynamics perspective

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Quadrupolar Nuclei in Solids

Cited by 27 publications

References 60 publications

New Methods and Applications in Solid-State NMR Spectroscopy of Quadrupolar Nuclei

New Methods and Applications in Solid-State NMR Spectroscopy of Quadrupolar Nuclei

Introduction to average Hamiltonian theory. I. Basics

Toward recording 33S NMR spectra of cross‐linked elastomers: Relaxation dynamics perspective

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Product

Resources

About

Toward recording ³³S NMR spectra of cross‐linked elastomers: Relaxation dynamics perspective