Theory of the Hyperfine Structure of Molecules: Application to3Pgr; States of Diatomic Molecules Intermediate between Hund's Cases (a) and (b)

摘要

In order to fully utilize the experimental accuracy of the high resolution afforded by radiohyphen;frequency spectroscopy, a fourthhyphen;order treatment of the energy is required. Especially, this fourthhyphen;order treatment is expected to be necessary in order to separate the quadrupolar interactions of light atoms in molecules from pseudoquadrupolar contributions to the energy due to magnetic hyperfine interactions which are off diagonal in therotational state.The example of3Pgr; states intermediate between Hund's Cases (a) and (b), whereJis still a good quantum number, is chosen to demonstrate the general techniques of such a fourthhyphen;order calculation. (Particular reference is made to thea3Pgr; state of isotopically substituted CO.) Van Vleck's method of reversed angular momentum is generalized to spherical tensor form in anticipation of future needs in the calculation of hyperfine structures of more complex systems. The spectroscopic parameters are explicitly written as matrix elements of the nonrelativistic wavefunctions in order that they be usable as checks on approximate molecular wavefunctions. Secondhyphen;order Stark and Zeeman effects are also discussed.