and
, we get
This frequency is of the same order of magnitude as that calculated by Einstein’s theory from the variation of the specific heat of hydrogen gas with temperature[45]. On the other hand, no absorption of radiation in hydrogen gas corresponding to this frequency is observed. This is, however, just what we should expect on account of the symmetrical structure of the system and the great ratio between the frequencies corresponding to displacements of the electrons and of the nuclei. The complete absence of infra-red absorption in hydrogen gas might be considered as a strong argument in support of a constitution of a hydrogen molecule like that adopted here, compared with model-molecules in which the chemical bond is assumed to have its origin in an opposite charge of the entering atoms.
As will be shown in [§5], the frequency calculated above can be used to estimate the frequency of vibration of more complicated systems for which an infra-red absorption is observed.
The configuration of two nuclei of charge
and a ring of three electrons rotating between them will, as mentioned in [§2], also be stable for displacements of the electrons perpendicular to the plane of the ring. A calculation gives