Raman spectrum of quartz

Abstract

Since quartz is transparent in the ultra-violet, the employment of the powerful technique for Raman-effect studies developed by Rasetti, in which the 2537 A. radiation from a water-cooled magnet-controlled mercury arc is the exciter, naturally suggests itself for this crystal. Rasetti's own studies included quartz, but his exposures were very short (20 min.) and it is therefore not surprising that he recorded only fourteen distinct frequency shifts as against the twenty shifts found earlier by Gross and Romanova with the 4358 A. radiation of the mercury arc as the exciter and exposures of the order of 120 hours. However, by prolonging the exposure with the Rasetti technique to 48 hours for a crystal 15 cm. long, I have recorded a very intense spectrum reproduced herewith, in which no fewer than forty-one distinct frequency shifts have been observed and measured. All the twenty-one newly observed frequency shifts are represented by relatively feeble lines and evidently belong to the Raman spectrum of the second order, namely, octaves and combinations of the fundamental frequencies of the quartz lattice. The accompanying table gives the measured frequency shifts in wave-numbers, the relative intensities of the lines being roughly indicated on an arbitrary scale within brackets.