Journal ArticleDOI
Nuclear Pure Quadrupole Relaxation and Its Temperature Dependence in Solids
D. E. Woessner,H. S. Gutowsky +1 more
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In this paper, the authors used a torsional molecular oscillator model to measure the T1 of the pure quadrupole T1 in cuprous oxide, paradichlorobenzene, 2,2-dichloropropane, t-butyl chloride, and methylene chloride at temperatures from 77°K to room temperature.Abstract:
The Cu63 and Cl35 pure quadrupole relaxation times have been measured by rf pulse techniques in cuprous oxide, paradichlorobenzene, 2,2‐dichloropropane, t‐butyl chloride, and methylene chloride at temperatures from 77°K to room temperature. The Cu63 T1 data agree with the ionic lattice model. The Cl35 T1 data for paradichlorobenzene agree with a torsional molecular‐oscillator model. For 2,2‐dichloropropane the Cl35 T1 values agree with a model based on field‐gradient fluctuations produced by reorienting CH3 groups. The more complicated T1 temperature dependences observed in t‐butyl chloride and methylene chloride appear to be the result of multiple thermal motions. The same can be said of our limited data on the Cl35 relaxation in 1,2‐dichloroethane. No discernible difference was found for the relaxation times of the two Cl35 resonance lines in methyl chloroform at 77°K.In general, the available proton T1 and linewidth data correlate well with our chlorine results; this agreement is discussed. The chlorine spin phase memory times are governed by the local magnetic fields except when decreased by spin—lattice lifetime broadening. The inverse linewidth parameters exhibit broadening by a distribution of field gradients. The fadeout of the Cl35 quadrupole resonance with increasing temperature in 2,2‐dichloropropane is the result of T1 broadening, while in t‐butyl chloride and methylene chloride it is produced by phase transitions.The Bayer model for spin—lattice relaxation by molecular torsional oscillations is treated in some detail, including a new approach which dispenses with some of his simplifying assumptions. A brief analysis is given of T1 for the case in which field‐gradient fluctuations are produced by random, large‐angle reorientations of groups near to the relaxed nucleus. The theory is presented for a null method of measuring the pure quadrupole T1. The method, which was used in most of our measurements, is similar to the Carr—Purcell 180°—90° pulse method for measuring nuclear magnetic T1's.The Cu63 and Cl35 pure quadrupole relaxation times have been measured by rf pulse techniques in cuprous oxide, paradichlorobenzene, 2,2‐dichloropropane, t‐butyl chloride, and methylene chloride at temperatures from 77°K to room temperature. The Cu63 T1 data agree with the ionic lattice model. The Cl35 T1 data for paradichlorobenzene agree with a torsional molecular‐oscillator model. For 2,2‐dichloropropane the Cl35 T1 values agree with a model based on field‐gradient fluctuations produced by reorienting CH3 groups. The more complicated T1 temperature dependences observed in t‐butyl chloride and methylene chloride appear to be the result of multiple thermal motions. The same can be said of our limited data on the Cl35 relaxation in 1,2‐dichloroethane. No discernible difference was found for the relaxation times of the two Cl35 resonance lines in methyl chloroform at 77°K.In general, the available proton T1 and linewidth data correlate well with our chlorine results; this agreement is discussed. The chlorin...read more
Citations
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Journal ArticleDOI
Cobalt-59 NQR spin-lattice relaxation times in trans-[COCl2(en)2][H5O2]Cl2∗ and trans-[COCl2(en)2]NO3☆
Journal ArticleDOI
Structural phase transition and motion of ammonium ions in α-NH4HgCl3 and its deuterated analog
TL;DR: In this paper, the temperature dependence of 35Cl NQR frequencies and spin-lattice relaxation times in the low-temperature phase of α-NH4HgCl3 as well as α-ND4HGCl3 is reported.
Journal ArticleDOI
Hindered rotation of CH3 groups and phenyl ring in clofibric acid (drug) studied by35Cl-NQR and1H-NMR spectroscopy
TL;DR: In this article, the rotations of two dynamically inequivalent methyl groups and the phenyl ring were detected and the relevant activation energies were determined for polycrystalline clofibric acid as a function of temperature.
Journal ArticleDOI
Nuclear quadrupole relaxation in chlorates
J. Kasprzak,J. Pietrzak +1 more
TL;DR: In this article, the 35 Cl pure quadrupole resonance frequency and relaxation times were carried out in the temperature range from 290 K to temperatures where the NQR signal vanishes, and it was found, that temperature dependence of the T 1 indicates some activation processes.
Journal ArticleDOI
Experimental considerations in determining spin-lattice relaxation times in nuclear quadrupole resonance spectroscopy
TL;DR: The effect of experimental conditions on the apparent spin-lattice relaxation time obtained in pulsed nuclear quadrupole resonance spectroscopy is investigated in this paper, where the inversion-recovery rate equation has been corrected to account for the nuclear magnetization dependence on tip angle in polycrystalline samples.
References
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Journal ArticleDOI
Effects of Diffusion on Free Precession in Nuclear Magnetic Resonance Experiments
H. Y. Carr,Edward M. Purcell +1 more
TL;DR: In this paper, the effect of diffusion on free precession in nuclear resonance has been studied, and a new scheme for measuring the transverse relaxation time is described, which largely circumvents the diffusion effect.
Journal ArticleDOI
Relaxation Effects in Nuclear Magnetic Resonance Absorption
TL;DR: In this article, the authors studied the effect of the thermal motion of the magnetic nuclei upon the spin-spin interaction in a rigid lattice and the line width of the absorption line.
Book ChapterDOI
Quadrupole Effects in Nuclear Magnetic Resonance Studies of Solids
Morrel H. Cohen,F. Reif +1 more
TL;DR: The field of electric quadrupole interactions in nuclear magnetic resonance can be divided roughly into two areas according to the relative magnitude of the nuclear quadrupoles interactions as discussed by the authors, which can be classified into two categories according to their relative importance.
Journal ArticleDOI
Structural Investigations by Means of Nuclear Magnetism. II. Hindered Rotation in Solids
H. S. Gutowsky,G. E. Pake +1 more
TL;DR: The experimental absorption line widths, for nuclei with spin 1/2, at nuclear magnetic resonance are given as a function of temperature for a number of molecular crystals.
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