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Proton Spin Relaxation In Dilute Methane Gas: A Symmetrized Theory And Its Experimental Verification, Peter A. Beckmann, M. Bloom, I. Ozier
Proton Spin Relaxation In Dilute Methane Gas: A Symmetrized Theory And Its Experimental Verification, Peter A. Beckmann, M. Bloom, I. Ozier
Physics Faculty Research and Scholarship
Nuclear spin relaxation in low density methane gas is investigated theoretically and experimentally. A theory is developed in which full account is taken of the tetrahedral symmetry of the molecule. For a nuclear Larmor frequency of 30 MHz, the time evolution of the nonequilibrium magnetization is measured as a function of density between approximately 0.005 and 17 amagats at temperatures of 110, 150, and 295 K. In all cases, exponential relaxation is observed. By using the theory in conjunction with the known spin rotation constants and rotational energy levels of CH4, the measured values of the relaxation rate …
Nuclear Spin Relaxation By Intramolecular Interactions In Gases Of Homonuclear Diatomic Molecules, Myer Bloom, Peter A. Beckmann, B C. Sanctuary
Nuclear Spin Relaxation By Intramolecular Interactions In Gases Of Homonuclear Diatomic Molecules, Myer Bloom, Peter A. Beckmann, B C. Sanctuary
Physics Faculty Research and Scholarship
The differential equations which describe the relaxation of macroscopic observables associated with nuclear spins in homonuclear diatomic molecules are derived using an expansion of the nuclear spin density matrix in terms of irreducible tensors. It is shown, using an intramolecular quadrupole mechanism, that the only difference between nuclear spin relaxation of the ortho- and para-species arises from the rotational states being restricted to odd and even values. This difference is vanishingly small at high temperatures so that the relaxation equations for nuclear magnetization become identical for both species. A previous paper predicting a difference even at high temperatures is …