  We report results of 27Al-NMR measurements on a single crystal of PrTi2Al20,
in which the ground state of Pr3+ ions in the crystalline electric field is the
nonmagnetic Gamma3 doublet. From the analysis of NMR spectra with the magnetic
field applied precisely along the <111> and <100> directions, we determined the
electric field gradient tensors for all three inequivalent Al sites (Al(1) ~
Al(3) sites) and the anisotropic Knight shifts for the Al(3) sites. The
hyperfine coupling tensor at the Al(3) sites is strongly anisotropic and much
larger than the classical dipolar coupling, indication importance of the
anisotropic hybridization between the conduction and f electron states.
