Alkali Recurrence Spectrum:

The heavy line in the top half of this figure is the quantum recurrence spectrum for lithium. The thin line in the top half is the semiclassical recurrence spectrum calculated using hydrogenic closed-orbits and including scattering from the core. The agreement is pretty good.


The dashed line in the lower half of the figure shows the quantum recurrence spectrum for hydrogen. The main peaks in lithium (top half) match up with those of hydrogen (lower half). Each peak is due to a hydrogenic closed orbit. The small additional peaks seen in lithium come from the scattering from one hydrogenic orbit to another by the core. The scattering also reduces the amplitudes of the main peaks in lithium compared to hydrogen by removing part of the flux from the neighborhood of the hydrogenic orbit on each return to the core.