The Infrared Spectrum of Heavy Water

Abstract

Samples of water vapor containing 90 and 40 percent of deuterium have been examined in the infrared, and the absorption bands v₂ and v₃ for D₂O and v₂ and v₁ for HDO have been located. The position of v₁ for D₂O is known from Raman scattering. Of the nine fundamental frequencies for the three varieties of water, eight have now been observed. The ninth, v₃ for HDO, should lie very close to the corresponding band for H₂O and is apparently completely masked. Computed values of these frequencies already available agree very well with the measured ones. A fair degree of resolution is obtained in the bands v₂. The fine structure observed agrees approximately with that predicted by using the molecular dimensions obtained by Mecke, viz., OH distance ∼0.95×10^—8 cm and apex angle ∼105°. The magnitude of the interactions is so great, however, that precise determinations of these constants must await a more complete solution of the mechanical problem.