The effects of quadrupole splitting of the central 27Al NMR line in polycrystalline kaolinite

Shulepov, Yu. V.; Litovchenko, A. S.; Melnikov, A. A.; Proshko, V. Ya.; Kulik, V.V

doi:10.1016/0022-2364(83)90024-0

Cited by 7 publications

(2 citation statements)

References 5 publications

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“…27Al DD/MAS NMR spectra of the sample Nl, measured at (A) 104.263 MHz and (B) 52.051MHz. Measuring conditions: repetition times of 2 s, spinning rates of (A)10.07 kHz and (B) 4.16 kHz, and pulse flip angles less than w/12. (The r pulse was calibrated for solution.)…”

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confidence: 99%

NMR study of kaolinite. 1. Silicon-29, aluminum-27, and proton spectra

Hayashi¹,

Ueda²,

Hayamizu³

et al. 1992

J. Phys. Chem.

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confidence: 99%

NMR study of kaolinite. 1. Silicon-29, aluminum-27, and proton spectra

Hayashi¹,

Ueda²,

Hayamizu³

et al. 1992

J. Phys. Chem.

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“…The definition of w o and t/are not unique but depend on authors. The second-order effects oW6 ~), when present, manifest themselves in well defined characteristic lineshapes [1][2][3][4][5][6][7][8] and give an additional shift [9,10] of the spectrum. These properties ate usually dealed with static and/ or very high [11,12] speed magic-angle spinning (MAS) probes performed in several strong static magnetic fields B0, or to a certain extent with variable angle spinning (VAS) [13,14], of double rotor (DOR) [15,16], or dynamic angle spinning (DAS) [17,18] probes.…”

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Excitation conditions for quantitative determination of quadrupolar spins with one pulse or spin-echo sequences in solid-state NMR

Man

1993

Appl. Magn. Reson.

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One of the major problems concerning quadrupolar spins in solid-state NMR is their quantification. Ir the optimal excitation conditions with one radio-frequency pulse are widespread known now, this is not the case with the spin-echo sequences. This paper reports some theoretical predictions and their limitations concerning quantification with the echo obtained with spin-echo resonances. To realize that, first, the relative line intensity of a transition ( m + 1, m) is defined in order to allow the comparison of results from different authors. Then results concerning one pulse excitation on a spin I= 3/2 are summarized. The condition of short pulse excitation is generalized to higher spins using the Pauli matrices applied to the two extreme cases: hard pulse of non selective excitation, and selective excitation. Finally the same procedure has been foUowed for the spin-echo sequence involving two x-pulses. It was shown that the optimum conditions are: both the pulse length must be sufficiently short, and the interpulse delay should be taken as short as the duration of the FID provided the phase of the second pulse alternates without changing the receiver phase. In these conditions, the relative echo amplitude depends lineady on the first pulse length and quadraticaUy on the second. The limitations are: the homonuclear magnetic dipolar interaction must be much smaller than the heteronuclear case which must be itself much smaller than the amplitude of the pulse. Furthermore, quantification with the echo requires the determination of the spin-spin relaxation time as well.

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