Spectroscopic constants and potential-energy derivatives for diatomic molecules of alkali halides

The potential-energy derivatives are derived directly from the experimental values of the spectroscopic constants for diatomic alkali halides. It is found that these derivatives are useful in predicting more accurately the values of the higher order spectroscopic constant (βe). Some interesting new relations showing the dependence of the potential-energy derivatives on internuclear distances have been investigated empirically. An attempt has been made to interpret these relations on the basis of interionic potentials.