Theory of muon spin depolarization in condensed phases of hydrogen isotopes

A theory of muon spin depolarization in the molecular ion ( H2μ)+(( D2μ)) formed in a crystalline phase of hydrogen isotopes is presented. It is shown that the molecular ion ( H2μ)+ has no time to thermalize during the muon lifetime, but after τ << τμ has time to transit to the lowest energy levels of the vibration-rotation spectrum. The depolarization of the muon spin is determined by the interaction of the ion's electric dipole moment with the lattice and by spin-rotation interactions VLS in the ion. This mechanism is analogous to that of 'muonium', replacing the hyperfine interaction by VLS. The results can explain the experimental data and in particular the absence of a strong isotopic effect