The Absorption Spectra of Certain Organic Liquids in the Near Infra-Red

Absorption spectra have been studied in the region from 0.8 to 2.5μ with an accuracy of 0.002μ for twenty-four organic liquids, including nine alcohols, six esters, two ethers, two aldehydes, and five miscellaneous compounds. The carbon-hydrogen linkage and other similar ones have been discussed as a probable source of the absorption. While certain inconsistencies are pointed out, no other explanation is available. The relative intensity of the various bands has been discussed and it is shown that the bands at 1.4 and 1.0μ and the two bands at 1.2 and 0.9μ evidently arise from different sources. The effect of homology is shown to be slight, which agrees with the conclusions of Weniger. An attempt has been made to get a relation between different band heads of a particular compound. The anharmonic series as suggested by Ellis, and the relation ${\nu }_n={\nu }_0{\mathrm{}\left(n\right)\mathrm{}}^{\frac{1}{2}}$ suggested by Gapon were both used with moderate success. The latter equation was modified so as to read ${\nu }_n=\frac{{\nu }_0}{{\mathrm{}\left(n\right)\mathrm{}}^{\frac{1}{2}}}$ and applied to part of the data of Weniger with moderate success.