The infra-red absorption spectra of quartz and fused Silica from 1 to 7·5 μ I-Experimental method

Abstract

A critical examination of the published data on the near infra-red spectra of silica shows that these are much less complete than appears commonly to be supposed. The absorption spectra of fused silica and of the ordinary ray in quartz have certainly been roughly examined over the whole region from 1 to 7·5 but these results have been so frequently quoted that an impression may be formed that many more independent measurements are on record than is actually the case. McGinnety* has collected the more important original figures and reduced them to common terms (i. e., absorption coefficient—wave numbers), from which it is clear that there are serious discrepancies between the results of different investigators—no one of whom has covered the whole region—not only with regard to the values of the absorption coefficients and wave numbers but also with regard to the shapes of the curves and the exigence or non-existence of certain bands, There is therefore room for a new and comprehensive experimental survey of the region.