The energy functions of the H2 molecules

Abstract §1. Comparison of Vibrational and Rotational Determinations of the Terms in the Expansion of the Force Function near the Equilibrium Position. Owing to the progress which has recently been made in the analysis of the spectrum of H2 we now have a good deal of information about the energy functions of some of the more stable H2 molecules. In dealing with this material we shall first compare the results given by the formulæ of Kratzer, Born and Hückel and Kemble, which depend mainly on vibration data and only in a secondary degree on rotational data, with those given by the method of Birge which involve only rotational data. It is satisfactory to find that the two methods do give a reasonably good agreement. This is important because without such agreement it is not possible to attack this problem by existing methods. In addition it shows that the analysis of the spectrum has proceeded along sound lines. A convenient account of these two methods will be found in the Report on Molecular Spectra in Gases.