MATPASS/CPMG: A sensitivity enhanced magic-angle spinning sideband separation experiment for disordered solids

Hung, Ivan; Edwards, Trenton; Sen, Sabyasachi; Gan, Zhehong

doi:10.1016/j.jmr.2012.05.013

Cited by 38 publications

(62 citation statements)

References 28 publications

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“…Nevertheless, even the current maximum achievable MAS rate (120 kHz) may not be enough to suppress extremely large anisotropies in materials like Li-ion batteries. Instead, the combined approach of the magic-angle turning (MAT) and the phase-adjusted sideband separation (PASS) to avoid the SSB issues is shown to be useful for such materials 84,85 . Therefore, the time limiting factor of the DQ/SQ correlation experiment is not sensitivity but phase cycling for the coherence selection.…”

Section: Sensitivitymentioning

confidence: 99%

Fast magic-angle sample spinning solid-state NMR at 60–100 kHz for natural abundance samples

Nishiyama

2016

Solid State Nuclear Magnetic Resonance

131

239

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Section: Sensitivitymentioning

confidence: 99%

Fast magic-angle sample spinning solid-state NMR at 60–100 kHz for natural abundance samples

Nishiyama

2016

Solid State Nuclear Magnetic Resonance

131

239

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“…MATPASS-CPMG is also another alternative to obtain sideband-free spectra. 35 The simultaneous fit of the five spectra with normalized intensities was performed with the mathematical software Maple TM , which is a trademark of Waterloo Maple Inc. The fit was made by the minimization of a χ 2 function calculated for the five experimental spectra.…”

Section: Solid-state Nmr Experimentsmentioning

confidence: 99%

Structure of Arsenic Selenide Glasses Studied by NMR: Selenium Chain Length Distributions and the Flory Model

et al. 2015

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International audienceFive homogeneous arsenic selenide glasses with target compositions As 2 Se 3 , AsSe 2 , AsSe 3 , AsSe 4.5 , and AsSe 6 were studied quantitatively by 77 Se Carr−Purcell−Meiboom−Gill magic-angle spinning NMR and transmission electron microscopy−energy-dispersive X-ray spectroscopy. The entire set of NMR spectra is simultaneously fitted with six distinct environments taking into account the effect of first and second neighbors on the position of the 77 Se resonance. The selenium chains are bound at each end to trivalent arsenic atoms, and the chain length distribution can be modeled with the Flory theory, which is well-known in polymer science and is used here for the first time to model the probability of finding each selenium environment in a selenide glass. No arsenic homopolar bond is detected in our experiments. ■ INTRODUCTION Chalcogenide glasses exhibit a wide range of physical properties such as infrared transparency, high refractive indices, and reversible amorphous-to-crystal transitions and can be easily shaped into optical devices. 1−6 Among them, the arsenic selenide glasses As x Se 1−x are considered to be a promising family because glassy As 2 Se 3 is a good candidate for all-optical switching 7 or for use as a mid-infrared laser source; 8 in addition, arsenic selenide glasses can be used for optic fibers. 9 Recent studies also investigated the possibility of preparing these glasses using microwave heating. 10 Numerous attempts were made to draw a link between the changes in the physical properties of arsenic selenide and the evolution of its molecular structure as the arsenic content varies, both at room temperature 11,12 and when the temperature is increased, 13 during aging of the glass, 14 or when irradiated with a laser. 15 To gain some insight into the arsenic selenide glass structures, recent studies relied on molecular dynamics 16−18 combined with anomalous X-ray scattering 19 or 77 Se solid-state NMR 20−23 to characterize the environments and connectivity of selenium and arsenic atoms. Many of these studies hint toward the existence of a small amount of As−As homopolar bond 12,16 with tetravalent arsenic atoms linked to two arsenic and two selenium atoms. 19 Moreover, 77 Se NMR spectroscopy can quantify three distinct selenium environments (selenium atoms linked to two, one, or zero arsenic atoms) and shows that there is some disorder in the distribution of the lengths of the selenium chains that link arsenic atoms together, as opposed to what is inferred in the chain-crossing model (i.e., when the selenium chains are of similar lengths). 20,23 Interestingly, it was suggested that the Flory model, 24 which describes the distribution of chain lengths in organic polymers, could be applied to inorganic polymers (mostly silicates) because the underlying chemical phenomena share striking similarities, especially for glasses with covalent bonds and no ionic species. 25−27 The Flory theory provides a very simple model for the probability, P(n), of finding a chain of length n, ...

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“…Recently, PASStype NMR experiments have successfully led to structural elucidation in a variety of crystalline and amorphous systems. [11a, [44][45][46][47][48][49] Here we employed 31 P MATPASS NMR spectroscopy to study the short-range structure of the local coordination of phosphorus in the two compounds La 3 Zn 4 P 6 Cl and La 3 Zn 4 P 6.6 Br 0.8 . La 3 Zn 4 P 6 Cl.…”

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confidence: 99%

Enclathration of X@La₄ Tetrahedra in Channels of Zn–P Frameworks in La₃Zn₄P₆X (X = Cl, Br)

et al. 2016

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Two new quaternary lanthanum zinc phosphide-halides were synthesized via high-temperature solid-state reactions. Their complex crystal structures were determined by a combination of X-ray diffraction and advanced solidstate 31 P NMR spectroscopy. La 3 Zn 4 P 6 Cl and La 3 Zn 4 P 6.6 Br 0.8 share a common structural feature: a polyanionic Zn-P framework with large channels hosting complex one-dimensional cations. The cations are built from X@La 4 tetrahedral chains with X = Cl (La 3 Zn 4 P 6 Cl) or Br 0.8 P 0.2 (La 3 Zn 4 P 6.6 Br 0.8 ). The X@La 4 tetrahedra share two vertices forming one-dimensional chains. To accommodate larger bromine-containing cations the Zn-P framework is rearranged by breaking and forming several Zn-P and P-P bonds. This results in the formation of a unique [P 3 ] 3− cycle, which is isoelectronic to cyclopropane. Analysis of the electron localization and orbital overlaps confirmed the presence of different chemical bonding in the Zn-P networks in the Cl-and Br-containing compounds. La 3 Zn 4 P 6 Cl was predicted to be a narrow bandgap semiconductor, while the formation of the [P 3 ] 3− units in the structure of La 3 Zn 4 P 6.6 Br 0.8 was shown to lead to a narrowing of the bandgap. Characterization of the transport properties confirmed both La 3 Zn 4 P 6 Cl and La 3 Zn 4 P 6.6 Br 0.8 to be narrow bandgap semiconductors with electrons as dominating charge carriers at low temperatures. La 3 Zn 4 P 6 Cl exhibits a n-p transition around 250 K. Due to the complex crystal structure and segregation of the areas of different chemical bonding, both title compounds exhibit ultralow thermal conductivities of 0.7 Wm -1 K -1 and 1.5 Wm -1 K -1 at 400 K for La 3 Zn 4 P 6 Cl and La 3 Zn 4 P 6.6 Br 0.8 , respectively.

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MATPASS/CPMG: A sensitivity enhanced magic-angle spinning sideband separation experiment for disordered solids

Cited by 38 publications

References 28 publications

Fast magic-angle sample spinning solid-state NMR at 60–100 kHz for natural abundance samples

Fast magic-angle sample spinning solid-state NMR at 60–100 kHz for natural abundance samples

Structure of Arsenic Selenide Glasses Studied by NMR: Selenium Chain Length Distributions and the Flory Model

Enclathration of X@La₄ Tetrahedra in Channels of Zn–P Frameworks in La₃Zn₄P₆X (X = Cl, Br)

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MATPASS/CPMG: A sensitivity enhanced magic-angle spinning sideband separation experiment for disordered solids

Cited by 38 publications

References 28 publications

Fast magic-angle sample spinning solid-state NMR at 60–100 kHz for natural abundance samples

Fast magic-angle sample spinning solid-state NMR at 60–100 kHz for natural abundance samples

Structure of Arsenic Selenide Glasses Studied by NMR: Selenium Chain Length Distributions and the Flory Model

Enclathration of X@La4 Tetrahedra in Channels of Zn–P Frameworks in La3Zn4P6X (X = Cl, Br)

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Enclathration of X@La₄ Tetrahedra in Channels of Zn–P Frameworks in La₃Zn₄P₆X (X = Cl, Br)