Infrared spectrum of HDO in water and in NaCl solution

The molar absorptivity of dilute HDO in water and in aqueous NaCl solutions was determined at temperatures between 10 and 85° in the spectral region from 4000 to 2000 cm −1 .The infrared band profiles for the OH and OD stretching fundamentals are single-peaked and devoid of shoulders, in contrast to the high-frequency shoulders recently observed in the Raman spectrum. It is shown that such shoulders do not contradict a single-peaked distribution of OH oscillators with respect to inter-molecular geometry. Absence of resolvable sub-bands in the spectrum of HDO in concentrated salt solutions indicates a wide distribution of ion–H 2 O interactions, akin to the distribution of H 2 O–H 2 O interactions in water.