The Raman Spectra of Gaseous Substances 1. Apparatus and the Spectrum of Methylamine

An apparatus is described by means of which the Raman spectra of gases may be obtained at pressures as low as 2–3 atmospheres and with exposure times of 3–6 hours. The fundamentals of this apparatus are a high intensity light source, a large scattering volume and a large aperture spectrograph camera. Nine lines in the spectrum of methylamine have been measured and are compared with previous measurements on the liquid. An interesting feature of this spectrum is the existence of four lines in the region of C–H valence vibrations, where but two are expected. This anomaly is interpreted in terms of a double resonance interaction.