Term Symbols And Spectral Details

In the LS coupling (Russell-Saunders coupling) scheme, the term symbols represent the combined total orbital angular momentum ( ) and total spin angular momentum ( ) of an atom. The term symbol is written as , where: - is the multiplicity (indicating the total number of spin states), - is the orbital angular momentum quantum number (denoted by letter: S, P, D, F,...), - is the total angular momentum quantum number ( ). The only term symbol that is valid in LS coupling is because it follows the correct rules for combining orbital and spin angular momenta, with a possible value for corresponding to the -orbital ( ) and . Thus, the correct answer is (D) .