MEASUREMENT OF SPIN-PHONON TRANSITION PROBABILITIES IN POTASSIUM CHROMICYANIDE

1967 ◽  
Vol 45 (10) ◽  
pp. 3269-3273 ◽  
Author(s):  
C. F. Weissfloch
Keyword(s):  
Experimental Method ◽  
Transition Probabilities ◽  
Lattice Relaxation ◽  
Experimental Results ◽  
Spin Lattice Relaxation ◽  
Direct Process ◽  
Spin Lattice ◽  
Van Vleck ◽  
Phonon Transition ◽  
Spin Phonon Transition

An experimental method based on the technique of microwave pumping was used to measure spin-phonon transition probabilities in dilute potassium chromi-cyanide. The set of numerical values obtained appears to indicate that the spin-lattice relaxation by the direct process of the cyanide-coordinated Cr3+ ion violates the quadrupolar selection rules. This behavior is in disagreement with the Kronig – Van Vleck theory, but is not contradicted by the experimental results of other workers.

Measurement of spin–phonon transition probabilities in ruby

1970 ◽  
Vol 48 (9) ◽  
pp. 1099-1103 ◽  
Author(s):  
M. El-Azab ◽  
C. F. Weissfloch
Keyword(s):  
Transition Probabilities ◽  
Relaxation Times ◽  
Phase Method ◽  
Relaxation Processes ◽  
Spin Lattice ◽  
X Band ◽  
Coupling Parameters ◽  
Lattice Coupling ◽  
Phonon Transition ◽  
Spin Phonon Transition

Measurements at X-band frequencies of relaxation times and spin–phonon transition probabilities in ruby grown by the "vapor phase" method were carried out. They demonstrate the existence of relaxation processes which cannot be related to the spin–lattice coupling parameters obtained from ultrasonic and static stress experiments.

SPIN-LATTICE RELAXATION BY THE DIRECT PROCESS OF Fe3+ IN POTASSIUM COBALTICYANIDE

1966 ◽  
Vol 44 (12) ◽  
pp. 3185-3196
Author(s):  
C. F. Weissfloch
Keyword(s):  
Magnetic Field ◽  
Relaxation Time ◽  
Point Charge ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Potassium Ferricyanide ◽  
Spin Lattice Relaxation ◽  
Direct Process ◽  
Spin Lattice ◽  
Satisfactory Prediction

The spin-lattice relaxation time of dilute potassium ferricyanide was measured as a function of the orientation of the static magnetic field in three orthogonal planes at 9.4 GHz and 1.75 °K.A calculation of the spin-phonon Hamiltonian applicable to the case of three Kramer doublets degenerate with respect to the cubic component of the crystalline bond is given. The theory was applied to the ferricyanide on the basis of Van Vleck's point-charge model.Despite the fact that the ferricyanide complex is known to be considerably covalent, it is found that the theory gives a satisfactory prediction of the observed angular dependence.

Intermolecular and intramolecular contributions to the proton spin-lattice relaxation of the liquid crystal 4-cyano-4′-n-pentyl-d11-biphenyl: nematic and supercooled nematic regions

1987 ◽  
Vol 65 (2) ◽  
pp. 115-121 ◽  
Author(s):  
John S. Lewis ◽  
E. Tomchuk ◽  
E. Bock
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Qualitative Agreement ◽  
Nonlinear Least Squares ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Experimental Results ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Fitting Parameters

The intermolecular and intramolecular contributions to proton spin-lattice relaxation in 4-cyano-4′-n-pentyl-d11-biphenyl (5CB-d11) have been measured as a function of temperature and frequency. The theories of relaxation in nematic liquid crystals are presented in a form suitable for nonlinear least squares fitting to the data, and the experimental results compared with appropriate theories. It is found experimentally that it is not possible to distinguish between the Freed and the Ukleja et al. theories on intramolecular spin-lattice relaxation or between the Zumer–Vilfan and the Ukleja et al. theories on intermolecular spin-lattice relaxation. All three theories are in more or less equal qualitative agreement with experimental results and yield fitting parameters of comparable physical plausibility.

The role of the ordinary and anharmonic Raman processes in Rb2PtI6

1978 ◽  
Vol 56 (11) ◽  
pp. 1461-1467 ◽  
Author(s):  
Robert G. C. McElroy ◽  
Robin L. Armstrong
Keyword(s):  
Nuclear Spin ◽  
Lattice Relaxation ◽  
Experimental Results ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Raman Process ◽  
Nuclear Spin Lattice Relaxation ◽  
Rare Opportunity

Measurements of iodine nuclear spin lattice relaxation in Rb2PtI6 provide a rare opportunity to directly measure the separate contributions of the ordinary and anharmonic Raman processes. It is shown that for this crystal one may separately determine W1 and W2 and that these rates may be uniquely related to the two Raman processes. The experimental results show that the anharmonic Raman process is dominant but not to the total exclusion of the ordinary Raman process.

scholarly journals Nuclear Spin-lattice Relaxation Rates of Ni and Ru in Fe

1998 ◽  
Vol 51 (2) ◽  
pp. 267 ◽  
Author(s):  
E. Beck ◽  
W. D. Brewer ◽  
T. Funk ◽  
E. Klein
Keyword(s):  
Thermal Cycling ◽  
Nuclear Spin ◽  
Lattice Relaxation ◽  
Heavy Ion ◽  
Experimental Results ◽  
Spin Lattice Relaxation ◽  
Experimental Uncertainty ◽  
Relaxation Rates ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation

We have determined the nuclear spin-lattice relaxation (SLR) rates of Ni and Ru as dilute impurities in iron using the method of thermal cycling on oriented nuclei. The samples were prepared by recoil implantation from the heavy ion reactions used to produce the radioactive Ni and Ru isotopes employed in the measurements. In the 3d impurity series, only Sc, Ti, and Cu remain to complete the systematics of the SLR in iron host; in the 4d series, values for Zr and Pd are still missing and the datum for Rh has a large experimental uncertainty. We discuss the comparison with theory and with other experimental results.

NH4+ Ion Motions in Some Ammonium Salts

1981 ◽  
Vol 36 (3) ◽  
pp. 205-209 ◽  
Author(s):  
Fevzi Köksal
Keyword(s):  
Hydrogen Bonding ◽  
Low Temperatures ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Experimental Results ◽  
Ammonium Salts ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Unit Cells ◽  
Good Agreement

Spin-lattice relaxation times of protons in polycrystalline (NH4)2SO4, (NH3OH)2SO4, (NH4)2HPO4, NH4VO3, (NH4)2CrO4, (NH4)2C2O4 • H2O and NH4HF2 salts were measured over the temperature range 100-430 K. The double minima in T1 for the first three compounds were attributed to the nonequivalent NH4+ ions in the unit cells. In NH4VO3, the double minima were attributed to the reorientations about two and three fold axes. However only one minimum in T1 was observed for (NH4)2CrO4, (NH4)2C2O4 • H2O and NH4HF2 and the relaxation mechanisms for the first three compounds were attributed to random reorientations of NH4+ ions. The experimental results are in good agreement with the calculated values by using the existing theoretical expressions. The discrepancies between experimental and calculated values for (NH4)2HPO4 and NH4HF2 at low temperatures were attributed to the tightness of the hydrogen bonding at those temperatures

Longitudinal spin-lattice relaxation in aqueous solutions of dysprosium(III) and copper(II) ions as an indicator of complex formation

1968 ◽  
Vol 46 (12) ◽  
pp. 2178-2180
Author(s):  
E. Bock
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Coordination Number ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Experimental Results ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Longitudinal Spin

Spin-lattice relaxation times of aqueous solutions of Dy(III) and Cu(II) in the presence of acetate ions were determined. The experimental results suggest that the coordination number with respect to the acetate ion appears to be 3 and 2 for the Dy(III) and Cu(II) ion respectively.

Electron spin–lattice relaxation of Ni2+

1969 ◽  
Vol 47 (16) ◽  
pp. 1753-1756 ◽  
Author(s):  
K. P. Lee ◽  
D. Walsh
Keyword(s):  
Electron Spin ◽  
Lattice Relaxation ◽  
Magnesium Nitrate ◽  
Spin Lattice Relaxation ◽  
Direct Process ◽  
Effective Spin ◽  
Strongly Coupled ◽  
Spin Lattice ◽  
Phonon Bottleneck ◽  
Spin Triplet

The electron spin–lattice relaxation rate by the direct process for Ni2+ in lanthanum magnesium nitrate is surprisingly fast (5 × 103 s−1 at 1.55 °K). Ni2+ is a non-Kramers ion, however, and consequently is strongly coupled to the lattice in most cases. The effective spin triplet and the absence of both hyperfine structure and phonon bottleneck are optimum requirements for a maser material.

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