On the infrared spectrum of solid hydrogen deuteride

Abstract

The spectrum of solid hydrogen deuteride has been studied in the far-infrared (80–200 cm−1) and mid-infrared (3600–4500 cm−1) regions using a Fourier transform spectrometer and a moderately high spectral resolution of 0.09 cm−1. Spectra of the liquid were also recorded for comparison purposes. The pure rotational R0(0) transition at 88 cm−1 was found to have an integrated intensity of 1.78 ± 0.10 cm−2, in good agreement with a recent theoretical prediction. The shape of R0(0) appears to be best represented as the sum of two near-Lorentzian components. These may be related to the presence or absence of nearest neighbor H2 or D2 impurities in the crystal. The fundamental band in the mid-infrared is more complicated, and its detailed shape is not completely understood at this time. The profile of the band in the 3710 cm−1 region of the R1(0) transition is compared with a recent theoretical calculation. The presence of numerous sharp lines due to Q1(1) transitions in impurity H2 molecules around 4150 cm−1 is also noted.