NUCLEAR QUADRUPOLE RESONANCE STUDIES IN CUPROUS OXIDE

1966 ◽  
Vol 44 (10) ◽  
pp. 2315-2328 ◽  
Author(s):  
K. R. Jeffrey ◽  
R. L. Armstrong
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Cuprous Oxide ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Quadrupole Moments ◽  
Spin Lattice ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

The 63Cu and 65Cu pure nuclear quadrupole resonance transitions have been investigated in a powder sample of cuprous oxide from 4.2 °K to 298 °K. The observed decrease in resonance frequency with increasing temperature is discussed in terms of the theory developed by Bayer and Kushida. The spin-lattice relaxation-time measurements above 20.4 °K are interpreted in terms of a coupling of the lattice phonons to the nuclear quadrupole moments via two phonon Raman processes. A rough estimate of the Debye temperature is made. The measured relaxation times at 4.2 °K are an order of magnitude shorter than predicted by the spin-phonon mechanism. Two other mechanisms are discussed: (i) a coupling of the spins to torsional oscillations; (ii) a coupling of the spins to paramagnetic impurities.

Potassium hexachloropalladate and potassium hexachloroplatinate: a comparative study using nuclear quadrupole resonance

1969 ◽  
Vol 47 (20) ◽  
pp. 2165-2169 ◽  
Author(s):  
Robin L. Armstrong ◽  
Douglas F. Cooke
Keyword(s):  
Temperature Dependence ◽  
Nuclear Quadrupole Resonance ◽  
Lattice Relaxation ◽  
Nuclear Quadrupole Resonance Frequency ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Lattice Mode ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Measurements of the temperature dependence of the nuclear quadrupole resonance frequency νQ and spin–lattice relaxation time T1 of the 35Cl nuclei in powdered samples of K2PdCl6 are reported. The data are qualitatively similar to earlier results for K2PtCl6 and are analyzed in the same manner. The temperature dependence of both νQ and T1 are dominated by the F1g rotary lattice mode of frequency ~ 41 cm−1. The data for K2PdCl6 and K2PtCl6 are compared and the parameters characterizing the NQR behavior tabulated. It is suggested that the quantitative explanation of the rather small differences observed might provide a challenging problem for a molecular orbital theorist.

Application of Nuclear Quadrupole Resonance Relaxometry to Study the Influence of the Environment on the Surface of the Crystallites of Powder

2015 ◽  
Vol 70 (6) ◽  
pp. 451-457 ◽  
Author(s):  
Nikolay Ya. Sinyavsky ◽  
Ivan G. Mershiev ◽  
Galina S. Kupriyanova
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Inverse Laplace Transform ◽  
Spin Lattice Relaxation ◽  
Two Dimensional ◽  
Surface Phenomena ◽  
Spin Lattice ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

AbstractThe results of the experimental study of the influence of the environment surrounding the surface of the crystallites of a KClO3 powder on the distribution of the spin–spin and spin–lattice relaxation times for 35Cl nuclear quadrupole resonance are described. It was found that the distributions of the spin–lattice relaxation times are unimodal and distributions of the spin–spin relaxation times are bimodal for all samples we studied. T1 – T2 and T1ρ – T2 correlations by means of the two-dimensional (2D) inverse Laplace transform are obtained. The efficiency of the method for the study of surface phenomena in solids is demonstrated.

Nuclear Quadrupole Resonance in Amorphous Semiconductors

1996 ◽  
Vol 51 (5-6) ◽  
pp. 603-610
Author(s):  
P. Craig Taylor
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Amorphous Semiconductors ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Structural Order ◽  
Quadrupole Resonance ◽  
Far From Equilibrium ◽  
Nuclear Quadrupole

Abstract Nuclear quadrupole resonance (NQR) has provided a valuable tool for investigating the local structural order in semiconducting glasses. Measurements of NQR lineshapes and spin-lattice relaxation times help elucidate the local structural order and the unusual vibrational properties, respectively, of these glasses. In addition, NQR lineshape measurements on samples that are made under conditions that produce solids whose structures are far from equilibrium, such as fast-evap-orated films or rapidly-drawn fibers, provide detailed information on the changes in the local structural order from that which occurs in the well-annealed amorphous semiconductors.

Relaxation of 121Sb NQR in Antimony Trichloride due to Raman Process

2001 ◽  
Vol 56 (11) ◽  
pp. 777-784 ◽  
Author(s):  
Noriaki Okubo ◽  
Mutsuo Igarashi
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Antimony Trichloride ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Raman Process ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Abstract The spin-lattice relaxation times of 121Sb nuclear quadrupole resonance in SbCl3 have been measured from 4.2 K to the m. p., 346 K. The result is analyzed with a theory of the Raman process based on co­ valency and discussed in comparison with the previous result for Cl nuclei.

Quadrupolar Relaxation of X Type Nuclei in R2MX6 and RMX3 Compounds

1975 ◽  
Vol 53 (12) ◽  
pp. 1141-1147 ◽  
Author(s):  
Henry M. van Driel ◽  
Robin L. Armstrong
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Relaxation Mechanism ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Mode Spectrum ◽  
Spin Lattice ◽  
Raman Process ◽  
Quadrupole Resonance ◽  
Quadrupolar Relaxation

Calculations of nuclear quadrupolar spin–lattice relaxation times are presented. The expressions obtained for the first order Raman and anharmonic Raman processes are applicable to a pure nuclear quadrupole resonance investigation of the X nuclei in R2MX6 and RMX3 solids. On the basis of realistic assumptions it is shown that the anharmonic Raman process will provide the dominant relaxation mechanism for these nuclei in these compounds. The relation between the spin–lattice relaxation time and the lattice dynamics is obtained explicitly without recourse to an assumed form of lattice vibrational normal mode spectrum. In favorable cases it is shown that the spin–lattice relaxation times can be related to Brillouin zone averaged rotary mode frequencies which are useful for the analysis of experimental data.

A Study of Complex Anionic Motions in (Me2NH2)2ZnCl4 Crystals by Means of Chlorine Nuclear Quadrupole Resonance Techniques

1990 ◽  
Vol 45 (3-4) ◽  
pp. 464-466 ◽  
Author(s):  
Hiroshi Yamamoto ◽  
Atsushi Ishikawa ◽  
Tetsuo Asaji ◽  
Daiyu Nakamura
Keyword(s):  
Phase Transition ◽  
Relaxation Time ◽  
Transition Temperature ◽  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Abstract Three 35Cl NQR frequencies were observed for (Me2NH2)2ZnCl4 at room temperature, indicating the existence of three crystallographically nonequivalent chlorines in the crystal. With decreasing temperature, the frequency of the lines increased almost linearly and disappeared below ca. 220 K near the reported phase transition temperature (ca. 215 K) detected on cooling. The three NQR lines faded out above room temperature because of the occurrence of rapid anionic reorientational motions disclosed from measurements of the 35Cl NQR spin-lattice relaxation time.

14N NQR Study of Mixed Complexes (NaNO2)1-x(ANO3)x : (A=K, Na)

1998 ◽  
Vol 53 (6-7) ◽  
pp. 620-624
Author(s):  
Y. M. Park ◽  
S. K. Song ◽  
Y. M. Seo ◽  
J. K. Jung ◽  
S. H. Choh
Keyword(s):  
Relaxation Time ◽  
Transition Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Rate Of Change ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Mixed Systems

14N nuclear quadrupole resonance of the system (NaNO2)1-x(ANO3) with A = K and Na in the x-range 0≤x<0.5 and the temperature range 77 K≤7<360 K has been studied. The 14N NQR frequency of NaNO2 and its line width do not change with x, the latter fact untrasting the results of other mixed systems such as Na1-xAgxNO2. This indicates that in (NaNO2)1-x(ANO3)x highly mobile lattice defects exist. The dependence on x of the rate of change in the spin-lattice relaxation time T1 near the transition temperature is discussed in terms of a correlated flipping motion of the NO-2 ion groups.

Chlorine Nuclear Quadrupole Relaxation and Cationic Motion in Trimethylsulfonium Hexachloroselenate(IV): [(CH3)3S]2SeCl6

1992 ◽  
Vol 47 (1-2) ◽  
pp. 274-276
Author(s):  
Makoto Kaga ◽  
Tetsuo Asaji ◽  
Ryuichi Ikeda ◽  
Daiyu Nakamurab
Keyword(s):  
Complex Anion ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Quadrupole Relaxation ◽  
Spin Lattice ◽  
Nuclear Quadrupole ◽  
Increasing Temperature ◽  
Nuclear Quadrupole Relaxation

AbstractThe 35Cl NQR spin-lattice and spin-spin relaxation times, T1Q and T2Q, respectively, and the 1HNMR spin-lattice relaxation time T1H at 32 and 60 MHz were determined for [(CH3)3S]2SeCl6 as functions of temperature. The rapid decrease of observed above ca. 250 K with increasing temperature was attributed to the onset of reorientation of the [SeCl6 ]2- complex anion with the activation energy Ea = 42 + 5 kJ mol -1 . When cooled from ca. 250 K, T1Q showed an anomalous decrease. This T1Q decrease was explained by electric field gradient modulation related to some cationic motion. Possible origins of the cationic motion are discussed

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