Interference effects in the spectrum of HD: V. the pure rotational and fundamental bands of liquid HD

Abstract

The infrared absorption spectrum of HD has been studied in the liquid phase at temperatures between 17 and 35 K. Results were obtained for the region of the pure rotational R0(0) transition in the far infrared (80–95 cm−1), and for the fundamental band in the mid infrared (3600–4000 cm−1), using a temperature-controlled moderate-pressure cell with a 1.5-cm path length and a Fourier-transform infrared spectrometer. The R0(0) line was found to have a symmetric shape, a rather narrow width (from 1.3 to 1.8 cm−1), and an intensity that is moderately enhanced by interference effects. The R1(0) transition was found to have a more complicated asymmetrie shape due to interference effects, and at low temperatures was found to consist of (at least) two components, which strongly resemble those observed in solid HD.