Relativistic effects Tensors Magnetic shielding Relativistic electron Molecular dynamics Nuclear magnetic shieldings Spin dynamics Stereochemistry Relativity Molecular Hamiltonian Spin-rotations Theoretical study Approximation algorithms Atoms Born-Oppenheimer Bromine compounds Chlorine compounds Correlation effect Linear response Molecular rotations Numerical results Perturbative expansion Quantitative result Random phase approximations Small components Spectral parameters Theoretical expression Yield differences Nuclear magnetic resonance Shielding