Critical temperature of the transition to a quadrupolar glass state in solid hydrogen

For the first time the possibility that quadrupolar glass in molecular solid hydrogen may undergo a transition to nonergodic states has been substantiated as an analog of the transition to a spin glass state. The thermodynamic stability with respect to fluctuations in replica pseudospin space is analyzed on the basis of the model Hamiltonian of the orientationally disordered phase of an ortho-para hydrogen mixture. An Almeida–Thouless-type stability condition is formulated within the the framework of the pseudo-Ising model Hamiltonian with random effective exchange interactions and a field of local anisotropy. The values obtained for the critical temperature and concentration enable us to estimate the region of the temperature concentration diagram of the orthocomponent where quadrupolar glass states can exist. This region coincides with the region of anomalous behavior of static and dynamic data from NMR experiments with ortho-para mixtures of solid hydrogen.