Review of calculation of magnetic hyperfine Interactions for a molecular system

Magnetic hyperfine interactions related to the nuclear and the electron spins of a molecular system consist of dipole-dipole interaction and the Fermi contact interaction. And it installed in the Gaussian program is to use to analyze NMR, ESR, $\mu $SR, and EPR experimental data. However, the Fermi contact term, important effect in a molecule, of magnetic hyperfine interaction has physical and mathematical problems on the vector potential definition. By contrasting the definitions of vector potential derived by the electromagnetic field theory with by the dipole-dipole interaction theory, it will be proved that the Fermi contact term cannot exist mathematically and physically. Most theoretical scientists have mistake is to choose wrong initial coordinates.