Vibration Spectra and Molecular Structure IV. The Infra-Red Absorption Spectra of the Double and Single Molecules of Formic Acid

Abstract

In the present study the absorptionspectrum of formic acid vapor between 1 and 15.5μ has been investigated under a variety of temperature conditions. The spectrum at room temperature gives essentially the absorption of the double molecules alone, while that at 140°C gives the absorption of the single molecules. The results are interpreted in terms of the hydrogen bonding existing in the double molecule. In addition an attempt to prepare and investigate pure formic acid‐d is reported.