Infra-red absorption of HDO in water at high pressures and temperatures

Abstract

By use of a specially designed cell with a sapphire window the absorption of the OD-stretching vibration of HDO in H₂O has been measured at frequencies from 2200 to 2900 cm^–1 and at temperatures and pressured from 30 to 400°C and from 50 to 4000 bars respectively. At the supercritical temperature of 400°C and pressures below 200 bars(corresponding to a density of water of 0.1 g/cm³) the rotational structure of the vibration band of free water molecules is observed. At higher density only one intensive absorption maximum with simple shape is observed at all temperatures. This is considered as support for the continuum model for water in the liquid and in the dense supercritical state.