SEARCH Articles Figures Tables Beyond the Orbital Approximation Orbital approximation Orbitals approximation The Approximations The LiH molecule approximate molecular orbital calculations The Orbital Approximation Helium The Orbital Approximation for Lithium The Orbitals The Wavefunctions of Many-Electron Atoms Can Be Described to a Good Approximation Using Atomic Orbitals Tin Orbitals and the Atomic Sphere Approximation