Infrared spectra of liquid hydrogen and deuterium

Abstract

Precise high-resolution spectra of liquid H2 and D2 in the regions of their fundamental vibrational bands (4000–5000 and 2900–3600 cm−1, respectively) are reported for various temperatures in the range 18–30 K. In hydrogen, concentrations for the.J = 0 para-H2 species of 25% (normal H2), 95%, and 99% were studied. In deuterium, normal D2, with 67% in the, J = 0 ortho state, was studied. These are the first published spectra of liquid D2. A detailed analysis of these results is not possible within present theories of collision-induced absorption, but it is hoped that their publication will stimulate theoretical interest.