Influence of the nuclear spin on the thermomagnetic torque

Abstract

The thermomagnetic torque in rarefied polyatomic gases is a result of the precession of the molecules around the direction of the external field. In the case of a strong magnetic field (Paschen-Back regime) this precession is determined by the rotational angular momentum of the molecules. In weak magnetic fields the angular momentum of diamagnetic molecules is coupled to the nuclear spin which influences the molecular precession and thus the thermomagnetic torque. In this paper experiments on the thermomagnetic torque in HD, n-D2, and n-H2 are reported in both strong and weak magnetic fields. Large deviations from an H / p behavior are found as a consequence of the spin coupling.