The Rotational Magnetic Moments of ${\mathrm{H}}_2$, ${\mathrm{D}}_2$, and HD Molecules. The Rotational Radiofrequency Spectra of ${\mathrm{H}}_2$, ${\mathrm{D}}_2$, and D in Magnetic Fields

The radiofrequency spectra of ${\mathrm{H}}_2$, ${\mathrm{D}}_2$, and HD molecules have been obtained for transitions corresponding to reorientations of the rotational angular momenta of the molecules. From these spectra the rotational magnetic moments of ${\mathrm{H}}_2$, HD, and ${\mathrm{D}}_2$ molecules in the first rotational states are found to be +0.8787±0.0070, +0.6601±0.0050, and +0.4406±0.0030 nuclear magneton, respectively, all of the moments being positive. The relative values are good to 0.2 percent and to this precision they are in the ratio 4: 3: 2 as expected theoretically. The rotational magnetic moment of ${\mathrm{H}}_2$ in the second rotational state was found to be just twice that in the first. From the rotational moment values, the high frequency contribution to the diamagnetic susceptibility of ${\mathrm{H}}_2$ is deduced to be (0.093±0.007) × ${10}^{-6\mathrm{}}$ per mole. Certain molecular interaction constants, including the interaction of the quadrupole moment of the deuteron with the inhomogeneous electric field of the molecule, are also obtained. The results are in complete agreement with similar measurements from the nuclear reorientation spectrum. Furthermore, the dependence upon orientation of the diamagnetic susceptibility of the hydrogen molecule in the first rotational state can be found. It is such that ${\xi }_{\pm 1}-{\xi }_0=-(4.5\mathrm{}\pm 2.0)\times {10}^{-31\mathrm{}}$ per molecule.