Motional Stark Effect on Li Vapor Photoabsorption in High Magnetic Fields

Calculation of the motional Stark effect for $B\sim 50$ kG shows it to become dominant along Rydberg series of light elements at $T\sim 1000°$C before the diamagnetic shift changes the spectrum from Rydberg to Landau type, thus accounting for the $\frac{1}{2}\hslash {\omega }_c$ spacing observed in Li. This spacing is preserved when both of the competing effects—motional Stark and Landau modulation—are strong. The spectrum appears to depend critically on the relative position of the thresholds for the onset of the two effects.