Elementary Properties of Angular Momenta in Diatomic Molecules

3 Elementary Properties of Angular Momenta in Diatomic Molecules 

The angular momenta that can occur in a diatomic molecule, AB, include spin of nucleus A or B, Ia, Ib orbital angular momentum of the ith electron, 1 spin of the ith electron, s and rotation of the nuclear framework, R. 

These fundamental angular momenta can couple to form  

With the exception of the angular momenta labeled by an asterisk, the notation employed is that specified by an international agreement among spectroscopists (Jenkins 1953, Mills et al., 1988, Hirota, et al., 1994). Various additional intermediate angular momenta, such as the electronic angular momenta of the ion core (Rydberg states) 

Angular momentum basis functions, AaM ), can be simultaneous eigenfunctions of three types of operators the magnitude A2, the projection of A onto the internuclear axis, Az, and the projection of A onto the laboratory 

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