The nuclear spin–spin coupling constant in He2

The scalar nuclear spin–spin coupling constant was calculated for the helium dimer using full configuration interaction (FCI) and EOM-CCSD methods. The Fermi-contact was found to have nonnegligible value of 1.3 Hz at $\text{R=5.6\hspace{0.05em}}\mathrm{a.u.},$ while the other contributions are zero. This suggests that the nuclear spin–spin coupling constants transmitted through van der Waals interactions are a much more common phenomenon than previously thought. All contributions exhibit sharp exponential decay with the internuclear distance.