Nuclear Spin and Magnetic Moment ofAl2713

The molecular beam magnetic resonance method has been applied to a determination of the gyromagnetic properties of the ${\mathrm{Al}}^{27}$ nucleus. The observed gyromagnetic ratio is 1.451±0.004 in units of $\frac{e}{2Mc}$. A comparison of this ratio with that obtained from the hyperfine splitting of several aluminum lines for various assumed values of the spin of ${\mathrm{Al}}^{27}$ fixes the spin of this nucleus as 5/2. The value of the magnetic moment is then found to be 3.628±0.010 nuclear magnetons. The sign of the moment is experimentally determined to be positive.