Anomalous behavior of the Grüneisen coefficient of solid hydrogen on the transition to the quadrupole glass state
Abstract
This paper discusses a hypothetical T–H phase diagram of a quadrupole glass in solid molecular hydrogen. The values of the critical temperature for freezing into the glassy state are identified with the positions of the minima at which a change takes place in the form of the temperature dependence of the Grüneisen coefficient. The temperature–concentration dependence of this latter is obtained from results of specific heat and pressure measurements by Haase et al. in the orientationally disordered phase of an ortho-para hydrogen mixture. The role of a magnetic field is fulfilled by the effective molecular fields characteristic of quadrupole systems. The results of the analysis confirm the validity of the concept of a quadrupole glass being analogous to a spin glass in an external field.