Senftleben—Beenakker Effect for the Viscosity of a Dilute Gas of Diamagnetic Diatomic Molecules

The effect of an external magnetic field on the viscosity of a dilute gas of rotating diamagnetic diatomic molecules is presented. A complete tensorial development in irreducible Cartesian tensors is given, the rotational states being treated quantum mechanically and the effect of inelastic collisions included. The magnetic-field dependence is given in terms of reduced square-bracket integrals and the variable H/p, where H is the magnetic-field strength and p, the equilibrium pressure of the gas. In this way it has been possible to include the cross effects existing between shear and bulk viscosities and which arise only in the presence of a magnetic field.