The authors present theoretical and experimental results of the anisotropic dielectric function epsilon 2( omega ) in YBa2Cu3O7. The theoretical spectra obtained from ab initio LDA-LMTO calculations show good agreement with those obtained by spectroscopic ellipsometry in the energy range 0.7 to 10 eV using untwinned single crystals. This allows them to assign the structures in the epsilon 2( omega )-function to specific interband transitions.
 

Physica C, 185-189 1473-4, 1991.