Nuclear magnetic shielding in the hydrogen molecule

Working within the adiabatic approximation in the gauge where the vector potential is zero at the nucleus, Ramsey's diamagnetic part of the shielding constant was calculated using an 87-term James-Coolidge-type wave function. The paramagnetic part of the shielding was determined by means of spin-rotation interaction and isotope-shift data. Results for the shielding constant in isotopes of the hydrogen molecule are reported for a range of temperatures between 0 and 500 K. For H₂ at 295 K and zero pressure, σ=26.366±0.070 ppm was obtained, with the error meant to take at least partly into account presently uncalculated nonadiabatic and relativistic effects. This value is in agreement with σ=26.23±0.18 ppm from experiment.