ABSTRACT
Atomic electron configurations give basic information about the stable atom in its ground state. Helium has a line spectrum similar to that of hydrogen. A term analysis of the spectral lines produces an energy level diagram which resembles that of hydrogen. It has been shown that a particular electron configuration can give rise to a number of possible states, which may have different energies and may have different allowed transitions. It is important to be able to label these states unambiguously and the label used is known as the 'term symbol' for the state in question. Consideration of the possible states in helium suggests that the important parameters defining the state are the orbital angular momentum (OAM), the total spin angular momentum and the multiplicity. The term symbol incorporates information on all these. The results for the relationships between energies of the different states in helium are special cases of general rules known as Hund's rules.
