The Infrared Spectrum of Fluoroform from 2.2 to 20μ

Abstract

The absorption spectrum of fluoroform has been investigated with a Perkin-Elmer double-pass spectrometer from 2.2 to 20μ. The resolution is sufficient to make possible an unequivocal assignment of all six fundamentals on the basis of the observed band envelopes. An anomaly is found in the symmetrical C–F stretching vibration; on the evidence now available this vibration should be assigned to the parallel band at 1209.3 cm−1 in the infrared (vapor) and to the polarized Raman line (liquid) at 1117 cm−1. Overtone and combination bands measured include the A1 and E components of the second harmonic of each of the three degenerate fundamentals. The separation of the maxima of the P and R branches of the parallel bands is discussed in relation to the theory of Gerhard and Dennison.