Rotational ordering and nuclear spin-lattice relaxation in solid methane

1978 ◽  
Vol 56 (9) ◽  
pp. 1182-1189 ◽  
Author(s):  
G. Briganti ◽  
P. Calvani ◽  
F. De Luca ◽  
B. Maraviglia
Keyword(s):  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Molecular Reorientation ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation ◽  
Special Cases ◽  
Lower Temperature ◽  
Lower Temperature Region

The proton spin-lattice relaxation time has been measured in solid CH4 down to 0.4 K. In the ordered phase at 9 < T < 20 K the relaxation process is induced by librons. The energy of the librons (~75 K) is in excellent agreement with the theoretical prediction by Yamamoto, Kataoka, and Okada. T1 has been found constant within experimental error between 0.4 and 9 K. The mechanism responsible for relaxation in this lower temperature region is attributed to the adiabatic molecular reorientation of the ordered T molecules. The cooling procedure has been found in special cases to affect the experimental results.

Proton Spin Relaxation in Low Density CH4–He Mixtures

1974 ◽  
Vol 52 (10) ◽  
pp. 876-879 ◽  
Author(s):  
Krovvidi Lalita
Keyword(s):  
Cross Section ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Low Density ◽  
Centrifugal Distortion ◽  
Molecular Reorientation ◽  
Density Region ◽  
Spin Lattice

The spin lattice relaxation time T1 was measured in CH4–He mixtures at 298 K for two compositions in the density region where T1 goes through a minimum. The data were fitted taking the centrifugal distortion effects into account. The cross section for molecular reorientation due to CH4–He collisions was obtained.

NUCLEAR SPIN-LATTICE RELAXATION TIME IN TIN

1978 ◽  
Vol 39 (C6) ◽  
pp. C6-1215-C6-1216
Author(s):  
H. Ahola ◽  
G.J. Ehnholm ◽  
S.T. Islander ◽  
B. Rantala
Keyword(s):  
Relaxation Time ◽  
Nuclear Spin ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation

Proton Spin Lattice Relaxation in the Dimethylammonium Group

1993 ◽  
Vol 48 (5-6) ◽  
pp. 713-719
Author(s):  
K. Venu ◽  
V. S. S. Sastry
Keyword(s):  
Experimental Data ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Methyl Groups ◽  
Dipolar Interactions ◽  
Spin Temperature ◽  
Spin Lattice ◽  
Molecular Group

Abstract A model for the spin lattice relaxation time of the protons of dimethylammonium in the Redfield limit and common spin temperature approximation is developed. The three fold reorientations of the methyl groups, the rotation of the whole molecular group around its two fold symmetric axis and possible correlations among these motions are considered. The effect of these processes on the dipolar interactions among the protons within the same molecular group is taken into account. The resulting relaxation rate is powder averaged and used to explain the experimental data in literature on [NH2(CH3)2]3Sb2Br9 . The analysis shows that dynamically inequivalent groups exist in this compound and that the effect of proposed correlation among the different motions on the final results is negligible.

NUCLEAR MAGNETIC RELAXATION IN GAS MIXTURES

1962 ◽  
Vol 40 (8) ◽  
pp. 1027-1035 ◽  
Author(s):  
D. Llewelyn Williams
Keyword(s):  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Gas Molecules ◽  
De Broglie Wavelength ◽  
Diffraction Effects ◽  
Good Agreement

Measurements of the proton spin–lattice relaxation time using pulse techniques have been made on the hydrogen–nitrogen, hydrogen–neon, and hydrogen–helium systems from room temperature to 60° K. The results are in good agreement with the Oppenheim–Bloom theory and illustrate the importance of the radial distribution of the gas molecules and of diffraction effects associated with the de Broglie wavelength.

Surface Induced Spin-Lattice Relaxation of Water in Tricalcium Silicate Gels

1991 ◽  
Vol 46 (8) ◽  
pp. 697-699
Author(s):  
F. Milia ◽  
Y. Bakopoulos ◽  
Lj. Miljkovic
Keyword(s):  
Grain Size ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Tricalcium Silicate ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Water Proton ◽  
Hydration Time ◽  
Spin Lattice ◽  
Stage Process

AbstractThe water proton spin-lattice relaxation time and recovery function of exchangeable water was measured in tricalcium silicate (C3S) gels. The measurements were carried out as a function of the hydration time and grain size. Results show that the hydration of (C3S) is a two stage process. A model is developped

81Br Nuclear Quadrupole Relaxation in Aluminium Tribromide

1995 ◽  
Vol 50 (8) ◽  
pp. 737-741 ◽  
Author(s):  
Noriaki Okubo ◽  
Mutsuo Igarashi ◽  
Ryozo Yoshizaki
Keyword(s):  
Room Temperature ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Quadrupole Relaxation ◽  
Spin Lattice ◽  
Raman Process ◽  
Nuclear Spin Lattice Relaxation ◽  
Nuclear Quadrupole ◽  
Nuclear Quadrupole Relaxation

Abstract The 81Br nuclear spin-lattice relaxation time in AlBr3 has been measured between 8 K and room temperature. The result is analyzed using the theory of the Raman process based on covalency. A Debye temperature of 67.6 K and covalency of 0.070 and 0.072 for terminal and 0.022 for bridging bonds are obtained. The correspondence of the latter values to those obtained from the NQR frequencies is low, in contrast to the previously examined compounds.

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