
doi: 10.1038/155452a0
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 studies1 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 Romanova2 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.
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 59 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 1% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
