Semiclassical interferences and catastrophes in the ionization of Rydberg atoms by half-cycle pulses

A multidimensional semiclassical description of excitation of a Rydberg ele ctron by half-cycle pulses is developed and applied to the study of energy- and angle-resolved ionization spectra. Characteristic phenomena. observabl e in these spectra such as interference oscillations and semiclassical glor y and rainbow scattering are discussed and related to the underlying classi cal dynamics of the Rydherg electron. Modifications to the predictions of t he impulse approximation are examined that arise due to finite pulse durati ons. [S1050-2947(99)50205-9].