SEMICLASSICAL STUDY OF THE IONIZATION SPECTRA OF RYDBERG ATOMS DRIVENBY INTENSE HALF-CYCLE PULSES

We present a new semiclassical method, based on an extension of the va n Vleck-Gutzwiller propagator, for the study of bound-free transition amplitudes of Rydberg H atoms, initially prepared in quasi-one-dimensi onal Stark states (n = 100), which are ionized by intense half-cycle p ulses. Oscillations in the ionization spectra are described by interfe rence between pairs of classical path amplitudes. The rate of the osci llations depends linearly on the initial principle quantum number n, a nd the amplitude of the oscillations depends sensitively upon the puls e length and whether the initial state is orientated with or against t he direction of electromagnetic polarization.