Here we report precision microwave spectroscopy of pure rotational transitions of the 207 Pb 19 F isotopologue. We use these data to make predictions of the sensitivity of the molecule to P-odd, T-even and P-odd, T-odd effects.

We measure and simulate numerically the Hanle effect and non-zero field level crossing signals in 85 Rb and 87 Rb atoms in a magnetic field at room temperature. Diode laser radiation from 4 mW cm −2 to 3.3 W cm −2 tuned to the D 2 absorption line of each isotope excites atoms into all the excited-state hyperfine levels simultaneously inside the unresolved Doppler profile. Polarization fluorescence detection is used to observe dark and bright resonances, as well as non-zero field level crossing resonances, for several excitation lines. A broad spectral line excitation model is applied to analyse the measured signals. The non-linear Zeeman effect is included in the model for both ground and excited states. Although the applied magnetic field does not exceed 80 G, several hyperfine levels of the excited state show a substantial deviation from the linear Zeeman effect.