The transport coefficients of ${}_{}{}^3{}_{}{}^{}\Sigma$ molecular oxygen in magnetic fields show large deviations from an $\frac{H}{p}$ law, even at moderate pressures and fields. This complex behavior is explained by the effect of a quadratic Zeeman splitting of the $\sigma =0\mathrm{}$ multiplets, superimposed on the normal linear splitting. Because the normal linear splitting is very small for $\sigma =0\mathrm{}$, the anomalous effects occur at fields far below the true Paschen-Back region. Collisionally uncoupled model calculations give the transverse viscosity coefficients in quite detailed agreement with experiment. The distinct behavior of the single- and double-frequency viscosity coefficients reflects distinct selections from the internal-state frequency spectrum, determined by weight factors ${\left|Y^{2\mu }\right(\theta ,\phi \left)\right|}^2$ in the orientation of $\overrightarrow{\mathrm{J}}$. The anomalous behavior of the even coefficients is predicted to be quite complex. In particular the $\frac{H}{p}$ curves of ${\eta }_1^{+}$ at about 4 Torr should show three steps, instead of the usual two, and the behavior of ${\lambda }_{\parallel }$ should be similar.

• Received 4 January 1971

DOI:https://doi.org/10.1103/PhysRevA.4.788