Dipole Moments for Diatomic Isotopomers

Vibrational amplitude effects for diatomic molecules can be straightforwardly calculated from spectroscopic data. Mean amplitudes and mean square amplitudes for diatomics are expressed in Equations 12.8a and 12.8b (see, e.g. Levine 1975) 

In Equation 12.8 Be is the rotational constant, Be = h/(8jt2I), (I is the moment of inertia), coe is the vibrational frequency, 27T(oe = (k/ix)1, (k the vibrational force constant and x the reduced mass), re the equilibrium bond length (isotope independent to reasonable approximation), and ae is the vibration-rotation interaction constant 

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