Nuclear spin relaxation in hydrogen gas

1969 ◽  
Vol 47 (13) ◽  
pp. 1355-1369 ◽  
Author(s):  
Krovvidi Lalita ◽  
Myer Bloom ◽  
John D. Noble
Keyword(s):  
Room Temperature ◽  
Rotational Quantum Number ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Hydrogen Gas ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Radial Dependence ◽  
Spin Lattice ◽  
Different Types

The proton spin–lattice relaxation time T1 in normal H2 gas has been measured as a function of temperature between 293 °K and 738 °K and pressure between 7 and 135 atm. These data and previous measurements at lower temperatures are analyzed in terms of a generalized theory which takes into account the influence of collisions which change the rotational quantum number J as well as those which only change MJ. It is concluded that collisions which change J play an important role even at temperatures as low as 200 °K. The relative importance of different types of inelastic collisions which give rise to changes in J is discussed. Some preliminary results of the radial dependence of the anisotropic H2–H2 interaction are given, but more accurate measurements of T1 as a function of ortho-H2 below room temperature are required to make a definitive interpretation.

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.

PROTON SPIN–LATTICE RELAXATION IN POLYATOMIC GASES

1961 ◽  
Vol 39 (8) ◽  
pp. 1093-1109 ◽  
Author(s):  
M. Bloom ◽  
M. Lipsicas ◽  
B. H. Muller
Keyword(s):  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Hydrogen Gas ◽  
Proton Spin ◽  
Intramolecular Interactions ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Oxygen Gas ◽  
The Mean ◽  
Solvent Molecules

The proton spin–lattice relaxation time T1 has been measured in gaseous samples of methane, ethylene, and ethane as a function of pressure at room temperature and also at 193° K for methane. In the pure gases T1 is proportional to density, p, at low densities indicating that intramolecular interactions couple the spin systems to the lattice, as is the case in hydrogen gas. T1/p at low densities gives information on the mean square angle through which the molecules are rotated per collision. Relaxation due to paramagnetic O2 is observed at higher densities when oxygen gas is added as an impurity. The relaxation probability per collision with an oxygen molecule is about 5 times larger for the ethylene–oxygen system than for the other two systems studied. This anomaly is discussed in terms of the theory of Oppenheim and Bloom. It is shown that a study of the temperature dependence of T1 due to O2 impurities provides a new way of obtaining detailed information on the Lennard–Jones parameters for the interaction between O2 and the solvent molecules.

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.

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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