Properties of the quadrupole glass phase in the presence of an external field gradient

A model of a solid disordered ortho-parahydrogen mixture with infinite long-range interaction J/sub ij/ between orthomolecules distributed in accordance with a normal law with first moment J0 is investigated. It is shown that the introduction of an external electric field gradient γ can give rise to a phase transition to an orientational phase. The possible existence of an orientational glass phase is established. The influence of the degeneracy of the hydrogen orthomolecules on the low-temperature thermal properties of these systems is demonstrated, and a condition of stability of the replica-symmetric solution is established. At low temperatures, this solution is stable for a large value of γ or J0.nctio