Physical Chemistry Third Edition

19

The Electronic States of Atoms.

III. Higher-Order Approximations

PRINCIPAL FACTS AND IDEAS

1. The electron–electron repulsions in multielectron atoms are included in
   several approximation methods:


2. The variation method allows calculation of upper bounds to ground-state
   energies.


3. The perturbation method allows approximate calculations of energies and
   wave functions for any states.


4. The self-consistent field method allows generation of the best possible
   orbital wave function.


5. The density functional method can in principle lead to the correct
   ground-state energy as a functional of the electron probability density.


6. The energy levels of multielectron atoms can be characterized by orbital
   and spin angular momentum values in the Russell–Saunders
   approximation.


7. The ground energy level of an atom can be identified using Hund’s rules.


8. The structure of the periodic table of the elements can be understood in
   terms of higher-order orbital approximations.

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