Rotation-Induced Resonance and Second-Order Quadrupolar Effects on Spin Locking of Half-Integer Quadrupolar Nuclei

Sun, Wei; Stephen, J. Todd; Potter, L; Wu, Yue

doi:10.1006/jmra.1995.0006

Cited by 50 publications

(64 citation statements)

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“…The RR condition is satisfied when the rf amplitude, o 1 ; and the rotor spinning speed, o r ; satisfy the following condition [30,31]:…”

Section: Rotary Resonancementioning

confidence: 99%

“…RR pulses also have been used in spin-1/2 systems to probe chemical shift anisotropy and dipole-dipole interactions [26][27][28][29]. The RR effects in half-integer quadrupolar systems were described previously as anomalies in the spin locking efficiencies in the suddenpassage regime [30,31], since they were not predicted by Vega's theory [32,33] for spin locking the central transition (CT) of half-integer quadrupolar nuclei. Presently, the low-spin locking efficiency is believed to be caused by mixing of the CT coherence into MQCs at RR conditions.…”

Section: Introductionmentioning

confidence: 99%

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Investigations of Low-Amplitude Radio Frequency Pulses at and away from Rotary Resonance Conditions for I = Nuclei

Logan

Urban

Walls

et al. 2002

Solid State Nuclear Magnetic Resonance

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Additional experimental evidence of rotary resonance effects for multiple-quantum coherence conversion in a spin-5/2 system is presented. Two-dimensional plots of the relative efficiency of MQ excitation and conversion are given as a function of radio frequency (rf) amplitude and pulse width. Data are presented for the excitation of five-quantum coherence (5QC), as well as for 5QC to three-quantum coherence (3QC) conversion, 5QC to IQC (the central transition coherence) conversion, and 3QC to IQC conversion. A two-fold increase in the signal-to-noise ratio is achieved by substituting low amplitude rf pulses in place of hard rf pulses for 5QC excitation and 5QC to 3QC conversion in a mixed multiple-quantum magic angle spinning (MAS) (MMQMAS) experiment. The anisotropic line shape for the low-amplitude rf pulse version of the MMQMAS experiment was observed to be distorted from the MAS line shape. The cause and implications of the distortion are discussed.

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“…The RR condition is satisfied when the rf amplitude, o 1 ; and the rotor spinning speed, o r ; satisfy the following condition [30,31]:…”

Section: Rotary Resonancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigations of Low-Amplitude Radio Frequency Pulses at and away from Rotary Resonance Conditions for I = Nuclei

Logan

Urban

Walls

et al. 2002

Solid State Nuclear Magnetic Resonance

View full text Add to dashboard Cite

show abstract

“…However, the conventional theory of the spin-locking of halfinteger quadrupolar nuclei under MAS conditions [158] does not take into account certain resonances that can occur when the rf nutation frequency is appropriately matched to the sample rotation frequency. Indeed, losses of spin-locking efficiency at these "rotary resonance" conditions were observed experimentally [159,160] and a partial theory of the effects was advanced [159] before further experiments proved that these losses in spin locking efficiency amounted to gains in the efficiency of multiple-quantum coherence conversion [161], or before full theories of the rotary effects were developed [162,163,164].…”

Section: Nmr Methods Of Manipulating Polarization In Quadrupolar Nuclmentioning

confidence: 99%

“…Some studies of quadrupolar spin dynamics in the presence of radiofrequency ir-radiation have been performed in the sudden passage regime, i.e., under fast spinning and low rf power conditions [158,159,160]. Several workers noted that unusual spin dynamics are observed at resonant conditions when the rf strength ω 1 is appropriately matched to the spinning speed ω R [159,160], as is discussed further in §5.6.5.…”

Section: Rotary Resonance Phenomenamentioning

confidence: 99%

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Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

Urban

2004

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Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantummechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters and associated appendices are intended to be pedagogical and include an introduction to the quantum mechanical theory of pulsed NMR spectroscopy and the time dependent theory of quantum mechanics.The third chapter describes investigations of the solid-state multiple-quantum magic angle spinning (MQMAS) NMR experiment applied to I = 5/2 quadrupolar nu-2 clei. This work reports the use of rotary resonance-matched radiofrequency irradiation for sensitivity enhancement of the I = 5/2 MQMAS experiment. These experiments exhibited certain selective line narrowing effects which were investigated theoretically.The fourth chapter extends the discussion of multiple quantum spectroscopy of quadrupolar nuclei to a mostly theoretical study of the feasibility of enhancing the resolution of nitrogen-14 NMR of large biomolecules in solution via double-quantum spectroscopy.The fifth chapter continues to extend the principles of multiple quantum NMR spectroscopy of quadrupolar nuclei to make analogies between experiments in NMR/nuclear quadrupolar resonance (NQR) and experiments in atomic/molecular optics (AMO). These analogies are made through the Hamiltonian and density operator formalism of angular momentum dynamics in the presence of electric and magnetic fields.The sixth chapter investigates the use of the macroscopic nuclear dipolar field to encode the NMR spectrum of an analyte nucleus indirectly in the magnetization of a sensor nucleus. This technique could potentially serve as an encoding module for the recently developed NMR remote detection experiment. The feasibility of using hyperpolarized xenon-129 gas as a sensor is discussed. This work also reports the use of an optical atomic magnetometer to detect the nuclear magnetization of Xe-129 gas, which has potential applicability as a detection module for NMR remote detection experiments.

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Characterization of Brønsted and Lewis acidity in zeolites by solid-state NMR and the recent progress in the REDOR technique

Blumenfeld

Fripiat

1999

Magn. Reson. Chem.

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Rotation-Induced Resonance and Second-Order Quadrupolar Effects on Spin Locking of Half-Integer Quadrupolar Nuclei

Cited by 50 publications

References 0 publications

Investigations of Low-Amplitude Radio Frequency Pulses at and away from Rotary Resonance Conditions for I = Nuclei

Investigations of Low-Amplitude Radio Frequency Pulses at and away from Rotary Resonance Conditions for I = Nuclei

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

Characterization of Brønsted and Lewis acidity in zeolites by solid-state NMR and the recent progress in the REDOR technique

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