Rotational Magnetic Moment, Magnetic Susceptibilities, and Electron Distribution in the Hydrogen Molecule

Measurements have been made on the rotational spectrum of H₂ in the state $I=J=1$ and in strong external magnetic fields. These measurements yield a value for the rotational magnetic moment of H₂ in the rotational state $J=1$ of μRH=(0.88291±0.00007) nuclear magnetons. From this, the high frequency contribution to the diamagnetic susceptibility is calculated to be ξHF=(1.64±0.16)×10^-31 erg gauss^-2 molecule^-1. Since the diamagnetic interaction with the external field increases as the square of the field, the high field measurements yield accurate determinations of the dependence of the diamagnetic susceptibility on the molecules' orientations which is found to be ξ_±1-ξ₀=-(3.66±0.20)×10^-31 erg gauss^-2 molecule^-1. ξHF and ξ_±1-ξ₀ may be combined to give a measure of the quadrupole moment of the electron distribution relative to the internuclear axis with the result that Qₑᵉˣᵖᵗ=(0.330±0.013)×10^-16 cm².