Term Symbols for Linear Molecules

2-11 TERM SYMBOLS FOR LINEAR MOLECULES Electronic states of a linear molecule may be classified conveniently in terms of angular momentum and spin, analogous to the Russell-Saunders term-symbol scheme for atoms. The unique molecular axis in linear molecules is labeled the axis. The combining atomic orbitals in any given molecular orbital have the same mi value. Thus an mi quantum number is assigned to each different type of MO, as indicated in Table 2-3. The term designations are of the form 

We shall work two examples in order to illustrate the procedure. 

State Symbols Corresponding to M/, Values in Linear-Molecule Electronic-State Classification 

Find Ml- The two electrons are placed in the a MO shown in Fig. 2-8, giving the configuration. This is the most stable state of Ha. The MO is r type, so each electron has mi 0. Then 

Find Ms. Since both electrons have mi = 0, they must have different values (the Pauli principle). Thus, 

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See also in sourсe #XX -- [ ]

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