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Deuteron NMR in solid D-T

1992; American Physical Society; Volume: 46; Issue: 2 Linguagem: Inglês

10.1103/physrevb.46.695

1095-3795

G. W. Collins, E. M. Fearon, E. R. Mapoles, R.T. Tsugawa, P. C. Souers, P. A. Fedders,

NMR spectroscopy and applications

The longitudinal relaxation times ${\mathit{T}}_{1}$ of the deuteron in solid deuterium-tritium (D-T) were measured from 2.5 to 5.0 K. They are shown to obey the Moriya-Motizuki equation, which means that relaxation takes place through the entirety of the J=1 ${\mathrm{D}}_{2}$ line. The total J=1 ${\mathrm{D}}_{2}$ plus J=1 ${\mathrm{T}}_{2}$ concentrations varied from 26% to 0.75%. The D-T relaxation times were shown to be independent of the NMR frequency. The inherent relaxation times ${\mathit{T}}_{11}$ of the D-T were in agreement with those of the deuteron in solid ${\mathrm{D}}_{2}$. It was shown that the deuteron ${\mathit{T}}_{11}$ values could be derived from those of the proton by adjusting the d term of the Hamiltonian. In contrast, the deuteron data for HD in the literature does not obey the Moriya-Motizuki equation, and the derived ${\mathit{T}}_{11}$ values are much larger than those of ${\mathrm{D}}_{2}$ and D-T. It was postulated that electric-field gradients from molecular size mismatches in the crystal cause restricted spin diffusion and a diffusion coefficient on the order of ${10}^{\mathrm{\ensuremath{-}}17}$ ${\mathrm{m}}^{2}$/s was calculated.