Indirect spin-spin interactions between nuclei bound in a molecule are well known in nuclear magnetic resonance, but such interactions between unbound atoms are less well studied and are often assumed to be zero. We present a precision calculation of this interaction between Xe129 and He3 nuclei in a gas. Relativistic, state-of-the-art electronic structure theory is used to compute the scalar coupling constant JR and the interatomic potential energy function VR as functions of the Xe-He internuclear distance R. Using virial expansion we find the nuclear spin enhancement factor κ=-0.0105±0.0015, in excellent agreement with recent experiments. This interaction is particularly important for precision measurements using nuclear spin comagnetometers.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics