Fermi contact 3 Approximation theory 2 Ground state 2 Hamiltonians 2 Magnetic fields 2 Magnetic shielding 2 Matrix algebra 2 Perturbation techniques 2 Tensors 2 Anisotropy 1 Chemical bonds 1 Coulomb and Breit two-body interaction operators 1 Diamagnetic spin orbital interactions 1 Differential equations 1 Dirac spinors 1 Eigenvalues and eigenfunctions 1 Electrons 1 Hydrogen 1 Magnetic molecular properties 1 Magnetic nucleus 1 Magnetic potential 1 Mathematical operators 1 No-pair approximation 1 Nuclear magnetic resonance 1 Nuclear magnetic shielding tensor 1 Numerical analysis 1 Paramagnetic resonance 1 Paramagnetic spin orbital interactions 1 Ramsey magnetic electron-nucleus interaction 1 Relativistic theory 1