Born-Oppenheimer 4 Linear response 4 Magnetic shielding 4 Molecular Hamiltonian 4 Molecular dynamics 4 Molecular rotations 4 Nuclear magnetic shieldings 4 Perturbative expansion 4 Relativistic effects 4 Relativistic electron 4 Small components 4 Spectral parameters Spin-rotations 4 Stereochemistry 4 Tensors 4 Theoretical expression 4 Theoretical study 4