Abstract
The contributions of the electrons in the H2-molecule to the moment of inertia is calculated by assuming irrotational flow for the motion of the electrons. Approximate expressions for the flow are obtained by means of a variational principle. It is found that the model accounts for at least 90% of the observed moment of inertia. Also the dependence of the moment of inertia on the internuclear spacing and the magnetic field of the electrons acting on the nuclei are calculated and found to be in rather good agreement with the experimental values.