Rotational diffusion of liquid toluene in confined geometry

Abstract
The effects of geometrical confinement on the molecular dynamics of liquid toluene in porous sol–gel silica glasses have been studied by the NMR method. The NMR deuteron spin–lattice relaxation times for toluene‐d8, ortho‐toluene‐d1, and para‐toluene‐d1 were measured as a function of temperature for bulk and confined liquids. The rotational diffusion tensors for overall, internal, and anisotropic rotational diffusion have been determined. The effect of geometrical confinement results in a considerable decrease of the rotational diffusion constants and leads to a lowering of the symmetry of the anisotropic rotational diffusion tensor.