Calculations are presented for the magnitude of the dispersion forces at rutile − vacuum − rutile, rutile − silica − rutile and rutile − water − rutile planar interfaces for the non-retarded limit. The calculations for rutile − vacuum − rutile and rutile − silica − rutile predict values of the Hamaker constant close to those determined through full spectral calculations using experimentally-determined interband transition strengths. However, subtle differences between these two approaches emerge when predicting trends in the Hamaker constant as a function of the orientation of the anisotropic rutile grains.

Keywords: Anisotropy, Hamaker constant, optical properties, planar interfaces, rutile, thin films