Correlation functions in the quadrupolar glass phase of solid hydrogen

A precise description of the molecular order parameters and their correlation functions that determine the NMR line shapes, damping of spin echoes, and the longitudinal nuclear relaxation in solid ortho-para hydrogen mixtures is given and the effects of fluctuations of the order parameters on the NMR measurements are discussed. This formalism is used to make precise definitions of terms such as "freezing," "dynamic gel," "glass formation," etc., that have been used in the literature to describe the NMR results. An operational definition of a "quadrupolar glass" is given in terms of the correlation functions and the different NMR techniques are analyzed to show what properties of the correlation functions can be deduced in each case. The time scale of the variations of the correlation functions probed by the different experiments is discussed in detail.

Перевод пока недоступен