A new method for measuring the magnetic moment of the proton in units of the nuclear magneton is described. The method differs from the work of others in that the cyclotron frequency of free low-energy ${\mathrm{H}}_2^{+}$ ions is measured with a low-power absorption technique as a function of magnetic field. The extrapolation technique of Franken and Liebes is utilized to correct for shifts produced by electrostatic fields. The measurements yield $\frac{{\mu }_p\left({\mathrm{H}}_2\mathrm{O}\right)}{{\mu }_n}=2.792\mathrm{}83\pm 0.00006$. This determination is approximately 50 ppm higher than the results of other workers.

• Received 3 February 1961

DOI:https://doi.org/10.1103/PhysRev.123.242