The Magnetic Moment of the Proton

The molecular beam magnetic resonance method has been employed to measure, in the same magnetic field, the frequency corresponding to a reorientation of the proton in the molecule NaOH and the frequency corresponding to a transition between certain of the h. f. s. levels of the ground state of both the atoms Cs^133 and In^115. From these data are calculated the ratio of the g factor of the proton, g₇, to the g factor of total electronic angular momentum, g₉, with the result g₇{g₉ (Cs, ^2S₁₂) }=15. 191110^-4 and g₇{g₉ (In, ^2P₁₂) }=45. 687710^-4. From a knowledge of the ratios g₉ ({Cs^133) }{g₉ (Na^23) } and g₉ ({In^115) }{g₉ (Na^23) } two entirely independent values of the ratio g₇{g₉ (Na^23) } have been obtained: From indium g₇{g₉ (Na) }=15. 192310^-4. From caesium g₇{g₉ (Na) }=15. 193110^-4. From the known value of gₒ{g₋}=2 (1. 100116), where gₒ and g₋ are, respectively, the g factors of electron spin and of orbital angular momentum, and on the basis of the assumptions that gₒ=g₉ and that g₋=1, we find, g₇=30. 420610^-40. 005percent. Including a small diamagnetic correction, the magnetic moment of the proton, ₇, is ₇= (15. 210610^-40. 005percent) Bohr magneton.