Bound States and Quasibound Resonances of Diatomic Systems

The importance of quasibound resonances is emphasized, with special reference to alkalinoble-gas systems. A modified WKB method for calculating the distribution and properties of quasibound resonances as well as of bound states is reviewed and applied to calculations of KAr and RbAr ground states. The calculated distribution of states in a Lennard-Jones 6-10 potential agrees precisely with the exact results of Mahan and Lapp. Inclusion of quasibound resonances is found to increase the total number of states by about $\frac{2}{3}$. Tunneling lifetimes much larger than typical collisional destruction times are found for most resonances.