Hyperfine potential energy curves of the heteronuclear diatomics HD, DT, and HT in an external magnetic field

Hyperfine interaction potential energy curves between two different ground state isotopic hydrogen atoms (H, D, or T) in the presence of an external magnetic field are constructed. It is found that the interaction between two isotopic hydrogen atoms is noncentral if relativistic effects are included. The eigenfunctions are expressed in terms of the basis set consisting of electronic and nuclear quantum numbers ‖ms1, mIa; mS2, mIb≳. Unlike the zero-field case with degenerate potential curves, there are 24 and 16 distinct curves for the systems H–D (or D–T) and H–T, respectively. Sample results are given for a magnetic field of B = 100 000 G, in particular. Interesting features at the true crossings and the avoided crossings between those potential curves will be described. With these accurately calculated potential curves, the accurate study of inelastic spin-exchange scattering between two different spin-polarized atoms (H↑, D↑, or T↑) can now be carried out.