SEMICLASSICAL MODEL OF LAMBDA-DOUBLET STATES IN DIATOMIC-MOLECULES

An intuitive picture of Lambda-doubling in diatomic molecules is prese nted using a semiclassical theory. A common view of Lambda-doubling as arising from electrons ''lagging'' behind the rotating internuclear a xis is shown to be misleading; rather, the eigenfunctions are symmetri c about the molecular axes and can be expressed as a superposition of pure nonrotating orbitals and travelling waves. These results are show n to be consistent with a full quantum treatment. We also examine, for the first time, time-dependent states, by monitoring expectation valu es of electronic- and nuclear-angular momenta. For low rotation freque ncy, the expectation value of the electronic-angular momentum locks on to the rotating internuclear axis, while for high rotation frequency i t locks onto the space-fixed total-angular momentum axis. At intermedi ate frequencies is a complicated behavior. (C) 1997 American Institute of Physics.