Approximation theory 8 Fermi level 6 Bromine compounds 4 Eigenvalues and eigenfunctions 4 Elimination of small component approach (ESC) 4 Error correction 4 Iodine compounds 4 Kinetic energy 4 Magnetic fields 4 Magnetic molecular properties 4 Magnetic moments 4 Magnetic shielding 4 Mathematical models 4 Mathematical operators 4 Nuclear magnetic shielding 4 Paramagnetism 4 Random-phase approximation (RPA) 4 Random-phase approximations (RPA) 4 Technetium 4 Density fluctuations 2 Electron emission 2 Electron energy levels 2 Electron scattering 2 Electron transitions 2 Electron traps 2 Electron-surfae interactions 2 Fermions 2 Hamiltonians 2 Harmonic analysis 2 Ionization 2