The Asymmetric Rotor. IV. An Analysis of the 8.5-μ Band of D2O by Punched-Card Techniques

Abstract

An analysis of the 8.5‐μ band of D₂O has been made by matching the observed transmission curve (published by Barker and Sleator) with a calculated curve. This was obtained by punched‐card techniques developed for analyzing incompletely resolved spectra, in which the relative intensity and position of every line was computed by rigid‐rotor theory for various choices of moments of inertia, and the absorption coefficients summed over a suitable ``slit width.'' The band is caused by a transition in which the induced electric moment is parallel to the intermediate axis of inertia. Its center is at 1179 cm⁻¹. The most satisfactory fit was obtained with moments calculated by the empirical equation of Fuson, Randall, and Dennison which applies an isotope effect to the known moments of inertia of H₂O, corrected slightly for the known values of Δ = I_C—I_B—I_A. The reciprocal moments are 15.38, 7.25, and 4.84 cm⁻¹ for the ground state, and 16.50, 7.33, and 4.79 cm⁻¹ for the upper state (the first deformation vibrational level).