Knowledge Bank

The molecular Zeeman effect was observed in methylene fluoride using a molecular beam maser spectrometer with the cavity in a 100 kilogauss magnetic field. This combination of high fields and high resolution (4 kHz at 22 GHz) provides unusually high resolution for these measurements. The rotational transition $303\to 212$ at 22 ,204 240 $\pm$ 2 kHz was observed in emission. The measured fluorine magnetic shielding anisotropics are $2\sigma cc-\sigma aa-\sigma bb=-335.\pm 35$ ppm and $\sigma aa-\sigma bb=37\pm 15$ ppm. Accurate susceptibility anisotropies and molecular quadrupole moments were also obtained.