Zeeman Effect in Rotational Spectra of Asymmetric-Rotor Molecules

The theory of rotational molecular magnetic moments is applied to the study of the Zeeman effect in microwave rotational spectra of asymmetric-rotor molecules. Measurements on absorption lines of ${\mathrm{H}}_{2}$O, ${\mathrm{D}}_{2}$O, and HDO are used to verify the theory, and the gyromagnetic tensors associated with these molecules are deduced. A discussion of electronic perturbation of rotational energy levels is appended.