Atomic term symbols via partitioning techniques

Two techniques for obtaining Russell–Saunders term symbols (terms) for equivalent electrons is presented. Both techniques are based on partitioning the n equivalent electrons into a set of α electrons and a set of β electrons. Fundamental tables are presented that give the number of states for the α or β electrons for all possible values M   α L ( M   β L ) and S α ( S β ). One interpretation of these tables leads to the total number of states of the n equivalent electrons for values of L and S . From this the number of terms for L and S is easily determined. Another interpretation of the fundamental tables gives the maximum number of terms for n equivalent electrons with values of L and S . From this the actual number of terms is obtained. Examples of equivalent p, d, f, and g electrons are provided. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011