The spin-lattice relaxation time has been studied in normal H₂ as a function of density and temperature in the range 293°K - 700°K. The measurements were made in the region where T₁ α [formula omitted]. The H₂ results have been interpreted using the Bloom-Oppenheim theory in which the transitions between different
J states were taken into account. The analysis indicates
that the resonant transitions (1,3↔3,1) and quasi-resonant transitions (1,2↔3,0) and (1,4↔3,2) contribute significantly
to the relaxation mechanism. The anisotropic inter-molecular potential between the two H₂ molecules which depends on the orientation of both the molecules could be given by quadrupole-quadrupole interaction while the part that depends on the orientation of one of the molecules alone was found to be adequately represented by a Lennard-Jones potential.
T₁ was measured in H₂ - He and H₂ - CO₂ mixtures as a function of density and composition in the temperature range 293°K - 700°K. The analysis indicates that the interaction potential for H₂ - He could be adequately described by a Lennard-Jones potential while the dominant interaction for H₂ - CO₂ could be given by quadrupole-quadrupole interaction. There were indications that the dependence of T₁/[formula omitted] in H₂ - He mixture on the percentage of He is non-linear above 150°K. However, this was not found to be the case in H₂ - CO₂ mixtures.
T₁ was also measured in CH₄ and CH₄ - He mixture as a function of density and composition in the same temperature
range. The data can be fitted by T₁/[formula omitted] = AT⁻ⁿ where n takes the value of 1.5 for pure CH₄ and 0.79 for CH₄ gas infinitely diluted in He. The analysis based on the existing theory for polyatomic gases shows that the intermolecular potential for CH₄ - CH₄ and CH₄ - He could be described by medium range potentials. The results indicate that the dependence of T₁/[formula omitted] on the percentage of He is not linear below 4OO°K. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/38093 |
| Date | January 1967 |
| Creators | Lalita, Krovvidi |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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