Infrared Lattice Bands of Quartz

Abstract

The infrared lattice bands of $\ensuremath{\alpha}$ quartz have been investigated at 297\ifmmode^\circ\else\textdegree\fi{}K from 5 to 37\ensuremath{\mu} in reflection and transmission with polarized light. Previously published measurements of the optical constants do not agree in this spectral range. It is shown that dispersion theory can fit the data within experimental error throughout the range, and accurate values of the dispersion parameters and the optical constants are obtained. This is the first accurate dispersion analysis of a complex spectrum. A study was made of the accuracy of the Kramers-Kronig method of analysis on this spectrum. The strength, width, and frequency of 14 optically active lattice vibrations are given, 4 of which have not previously been established. From a consideration of published Raman data, 10 of the resonances are assigned according to symmetry type as fundamental vibrations.