High Resolution Raman Spectroscopy of Gases: Ix. Spectra of H2, Hd, and D2

The pure rotational lines and the Q branch lines of the 1–0 vibrational bands of H 2 , HD, and D 2 have been photographed with a 21 ft. grating spectrograph. From these spectra, a complete set of constants for the ν = 0 and 1 levels of all three molecules have been determined. When these constants are combined with Herzberg's results of the forbidden infrared spectra of H 2 and HD they lead to improved values of the electronic ground state constants of H 2 and HD. The leading terms in the Dunham power series expansion of the potential are calculated for H 2 and HD and are found to be mutually consistent. The isotopic relations are obeyed within experimental accuracy, and the small constants D e , B e , and H e , are in agreement with values given by theoretical formulae.