A New Infra-red Absorption Band of Liquid Water at 2.52μ

The absorption of liquid water in the spectral region from 2. 00 to 2. 65 was measured by means of a thermopile and glass prism spectrometer with a slit width of 100 angstroms in a search for a weak absorption band predicted by Ellis as a combination band occurring in liquid water but not in water vapor. A band was found with a peak at 2. 52 and with a maximum absorption coefficient of about 34. This is the fifth absorption band to be found in the spectrum of liquid water that has no counterpart in the spectrum of water vapor.