  We present numerical and analytic results for uniaxial and biaxial order at
the isotropic-nematic interface within Ginzburg-Landau-de Gennes theory. We
study the case where an oblique anchoring condition is imposed asymptotically
on the nematic side of the interface, reproducing results of previous work when
this condition reduces to planar or homoeotropic anchoring. We construct
physically motivated and computationally flexible variational profiles for
uniaxial and biaxial order, comparing our variational results to numerical
results obtained from a minimization of the Ginzburg-Landau-de Gennes free
energy. While spatial variations of the scalar uniaxial and biaxial order
parameters are confined to the neighbourhood of the interface, nematic
elasticity requires that the director orientation interpolate linearly between
either planar or homoeotropic anchoring at the location of the interface and
the imposed boundary condition at infinity. The selection of planar or
homoeotropic anchoring at the interface is governed by the sign of the
Ginzburg-Landau-de Gennes elastic coefficient L_2. Our variational calculations
are in close agreement with our numerics and agree qualitatively with results
from density functional theory and molecular simulations.
