Refractive Index and Optical Dispersion of In2O3, InBO3 and Gahnite

O. Medenbach

Institut für Mineralogie, Fakultät fur Geowissenschaften, Ruhr-Universität Bochum,
            Universitätstraße 150, D-44780 Bochum

Theeranun  Siritanon, M. A. Subramanian

Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003

R.D. Shannon

Geological Sciences/CIRES, University of Colorado, Boulder, Colorado 80309

R. X. Fischer

Fachbereich Geowissenschaften, Universität Bremen, Klagenfurter Straße, D-28359 Bremen. 

George R. Rossman

Division of Geological and Planetary Sciences, California Institute of Technology,
Pasadena, California 91125-2500, USA



Refractive indices of In2O3, In2-xSnxO3, InBO3 and 2 different gahnite crystals (Zn0.95Fe0.05Al2O4  and  Zn0.91Mg0.04Mn0.03Fe0.03Al1.99Fe0.01O4)  were measured at wavelengths of 435.8 to 643.8 nm and were used to calculate n at lambda = 589.3 nm (nD ) and at lambda = infinity (ninfinity) using the one-term Sellmeier equation  1/(n2-1) = -A/lambda2 + B. Total polarizabilities, atotal, were calculated from ninfinity and the Lorenz-Lorentz equation. Refractive indices, nD and dispersion values, A, are, respectively, 2.093 and 133 x 10-16 m2 for In2O3; 2.0755 and 138 x 10-16 m2 for In2-xSnxO3; 1.7995 and 56 x 10-16 m2 for Zn0.95Fe0.05Al2O4; 1.7940 and 57 x 10-16 m2 for Zn0.91Mg0.04Mn0.03Fe0.03Al1.99Fe0.01O4  and no  = 1.8782 and ne = 1.7756 and <63> x 10-16 m2 for InBO3. The lack of consistency of the polarizabilities of Zn2+ in ZnO and In3+ in In2O3 with the Zn2+ and In3+ polarizabilities in other Zn- and In-containing compounds is correlated with structural strain and very high dispersion of ZnO and In2O3.