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.

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.

35Cl NQR Studies of Bismuth Trichloride

1997 ◽  
Vol 52 (8-9) ◽  
pp. 614-620
Author(s):  
P. K. Babu ◽  
J. Ramakrishna
Keyword(s):  
Temperature Dependence ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Positive Temperature Coefficient ◽  
Spin Lattice Relaxation ◽  
Positive Temperature ◽  
Lattice Vibrations ◽  
Spin Lattice ◽  
Quadrupole Resonance ◽  
35Cl Nqr

Abstract The temperature dependence of the 35Cl nuclear quadrupole resonance (NQR) frequency and spin lattice relaxation time (T1) are studied in crystalline BiCl3 , in the range 40-300 K. The positive temperature coefficient observed for one of the 35Cl resonances is explained in terms of the strong intermolecular interactions that exist in this compound. Variation of with temperature is found to be similar at the chemically inequivalent halogen sites. Semiclassical descriptions based on torsional oscillator dynamics are found to be inadequate for explaining the spin lattice relaxation. T1 (T) data follow an AT2 + BT3 type behaviour, indicating that the anharmonic nature of the lattice vibrations plays a significant role in determining the temperature dependence of T1 at high temperatures.

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.

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.

scholarly journals Pressure Dependence of the Chlorine NQR in Three Solid Chloro Anisoles

2001 ◽  
Vol 56 (11) ◽  
pp. 764-772 ◽  
Author(s):  
K. S. Suresh ◽  
K. P. Ramesh ◽  
C. Raghavendra Rao ◽  
J. Ramakrishna
Keyword(s):  
Relaxation Time ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Linear Variation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Temperature Coefficients ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Abstract The 35C1 Nuclear Quadrupole Resonance (NQR) frequency (VQ) and spin lattice relaxation time (T1) in the three anisoles 2,3,4-trichloroanisole, 2,3,6-trichloroanisole and 3,5-dichloroanisole have been measured as a function of pressure upto 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three com­ pounds show a non linear variation of the NQR frequency with pressure, the rate of which is positive and decreases with increasing pressure. In case of 3,5-dichloroanisole the value becomes negative in the higher range of pressure studied. The spin lattice relaxation time T1 in all the three compounds shows a weak dependence on pressure, indicating that the relaxation is mainly due to the torsional motions.

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