- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Nuclear spin relaxation in gas mixtures
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Nuclear spin relaxation in gas mixtures Lalita, Krovvidi
Abstract
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.
Item Metadata
Title |
Nuclear spin relaxation in gas mixtures
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
1967
|
Description |
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.
|
Genre | |
Type | |
Language |
eng
|
Date Available |
2011-10-19
|
Provider |
Vancouver : University of British Columbia Library
|
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.
|
DOI |
10.14288/1.0085827
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
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.