Band Series in Infra-Red Absorption Spectra of Organic Compounds. I

The frequencies of a series of outstanding absorption bands characteristic of organic liquids, previously attributed by the author to vibrations between atoms of a carbon-hydrogen pair, are shown to fit the equation, ${\nu }_n·{10}^{-12\mathrm{}}=47.37n-0.783\mathrm{}{n}^2,$ where $n=1, 2, \dots \dots ., 10$. Many of the bands of secondary intensity in the spectra of compounds containing a carbon-carbon bond have their frequencies expressed by ${{\nu }^{\prime }}_n·{10}^{-12\mathrm{}}=10.71n.\mathrm{}$ where $n=1, 2, \dots .., 28$. Practically all other bands observed below 7μ in such spectra can be accounted for by combinations of low frequency members of these two series, ${\nu }_c={\nu }_m+{{\nu }_n}^{\prime }$. Measurements on bands occurring between 2μ and 3μ were made from records obtained with a new registering spectrograph. A number of such spectra are shown.