Physical Review A
American Physical Society
Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. We derive an alternative version of closed-orbit theory that applies when the external fields are time dependent. We compare the results of this theory with experiments on lithium atoms in a weak oscillating electric field.
Haggerty, M. R. and Delos, John B., Recurrence Spectroscopy in Time-Dependent Fields (2000). Physical Review A, 61(5).