Effect of pressure on the temperature of the displacive to order–disorder crossover associated with the structural phase transition in K2OsCl6

The 35Cl nuclear quadrupole resonance spectrum of K2OsCl6 is studied as a function of applied hydrostatic pressure in the temperature range bracketing the temperature of the rotational phase transition. The data suggest that the effect of increasing pressure is to increase the lattice dimensionality of the correlated rotational fluctuations that drive this phase transition.