Rotational Magnetic Moments of Alkali-Halide Molecules

The rotational magnetic moments of a number of alkali-halide molecules have been measured by the molecular-beam magnetic-resonance technique. The gyromagnetic ratios in units of nuclear magnetons are: Only the absolute values were determined experimentally. However, the absolute values are reasonably consistent with the theoretical ones, so signs from the theory are listed above in parentheses. It is shown that for weak fields the molecular rotational magnetic moments do not correspond directly to the peaks of the reasonance curves. A statistical analysis has been carried out to determine the rotational $g$ values from the peaks of the observed resonances. Since the correction is large (up to 50%), the above results would be wrong by an amount beyond the indicated experimental error if the interpretation of the correction is not valid. No such uncertainty arises in the LiF measurements or in other rotational-moment measurements where the correction does not need to be made. The measured values determined in accordance with the above analysis are found to be in good agreement with the predictions from a theory of Foley. The spin-rotational interaction constant of ${\mathrm{F}}^{19}$ in ${\mathrm{Cs}}^{133}$ ${\mathrm{F}}^{19}$ has been measured by a new method to be 13.5±2.5 kc/sec.