Infrared studies of Ar(H-2)(2) at low temperature and high pressure

An extensive infrared absorption study of the compound AT(H-2)(2) in the range of pressure from 5 to 90 GPa, and between 30 It and room temperature is presented. This study has permitted the identification and assignment of high-frequency and low frequency vibron-phonon combination bands, as well as of the roto-vibrational bands. Spectra changes lowering temperature, with the appearance of the Q(1)(0) vibrational peak, are interpreted as arising from conversion of ortho-hydrogen into para-hydrogen in the solid.