International
Tables for Crystallography Volume D Physical properties of crystals Edited by A. Authier © International Union of Crystallography 2013 |
International Tables for Crystallography (2013). Vol. D, ch. 1.6, p. 157
Section 1.6.3.3. The dielectric impermeability tensor^{a}Department of Physics, University of Oxford, Parks Roads, Oxford OX1 3PU, England, and ^{b}Department of Earth Sciences, University of Oxford, Parks Roads, Oxford OX1 3PR, England |
It has been seen how the refractive indices can be described in a crystal in terms of an ellipsoid, known as the indicatrix. Thus for orthogonal axes chosen to coincide with the ellipsoid axes, one can write where , and . One can write this equation alternatively as where the are the relative dielectric impermeabilities. For the indicatrix in any general orientation with respect to the coordinate axesThus the dielectric impermeability tensor is described by a second-rank tensor, related inversely to the dielectric tensor.