Solid H2 and D2: Remarkable differences in some NMR properties.

The differences in the observed properties of solid H2 and D2 are reviewed, and in particular those encountered in NMR experiments. The failure to detect a sharp NMR (I=1) impurity ‘‘isolated pair’’ spectrum in p-D2 is discussed in terms of a larger crystalline field than in H2, where an intense and sharp pair spectrum has been observed. Furthermore, we discuss the dramatic (I=1) solid echo signal loss with decreasing temperature which is observed in solid D2, but not for solid H2. A theory of the solid echo damping through orientational fluctuations is developed. This theory accounts for the observed solid echo decay in D2 as a function of the pulse spacing time τ and leads to an estimation of the order parameter fluctuation amplitude and the correlation time τc. However, the theory cannot account for the loss of spin (as determined from Curie’s law), which must occur for very small values of τ that are not covered by the theory. Disciplines Physics | Quantum Physics This journal article is available at ScholarlyCommons: http://repository.upenn.edu/physics_papers/405 PHYSICAL REVIEW B VOLUME 49, NUMBER 6 1 FEBRUARY 1994-II Solid Hz and Dq. Remarkable difFerences in some NMR properties A. B. Harris Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 1910$ 6-996 H. Meyer and X. gin Department of Physics, Duke University, Durham, North Carolina, 27708 09-05 (Received 3 September 1993) The difFerences in the observed properties of solid H2 and D2 are reviewed, and in particular those encountered in NMR experiments. The failure to detect a sharp NMR (I = 1) impurity "isolated pair" spectrum in p-D2 is discussed in terms of a larger crystalline 6eld than in H2, where an intense and sharp pair spectrum has been observed. Furthermore, we discuss the dramatic (I = 1) solid echo signal loss with decreasing temperature which is observed in solid D2, but not for solid H2. A theory of the solid echo damping through orientational fluctuations is developed. This theory accounts for the observed solid echo decay in Dz as a function of the pulse spacing time r and leads to an estimation of the order parameter Huctuation amplitude and the correlation time 7, However, the theory cannot account for the loss of spin (as determined from Curie's law), which must occur for very small values of 7 that are not covered by the theory.