We report the results of our observations of liquid parahydrogen in the mid
-infrared and of liquid parahydrogen and orthodeuterium in their first and
second overtone regions using a Bruker IFS 120 HR Fourier transform spectro
meter. We have determined intensity parameters for individual absorption fe
atures where possible and indicate analogies between the spectrum of the li
quid and the corresponding spectrum of the solid phase of the hydrogens.