Local polarization distribution in quadrupolar glasses

We consider the semimicroscopic symmetry-adapted random-bond-random-field model of quadrupolar glasses such as NaCN:KCN and KBr:KCN, assuming strong lattice anisotropy which restricts the equilibrium orientations of the CN molecules to a set of discrete directions along the cubic [100] axes. Applying the replica theory of orientational glasses, we calculate the probability distribution W(p(1),p(2)) for the two independent components of local quadrupolar polarization p(1) and p(2) in the replica-symmetric quadrupolar glass phase. The reduced distributions W-2(p(2))=integral W(p(1),p(2))dp(1) and W-1(p(1))=integral W(p(2),p(1))dp(2) are shown to be related to the quadrupole-perturbed NMR line shape I(v) of the N-14 nucleus.