A. Haffmans et al., PREDICTION OF A NEW PEAK IN 2-FREQUENCY MICROWAVE IONIZATION OF EXCITED HYDROGEN-ATOMS, Physical review letters, 73(2), 1994, pp. 248-251
We report the first theoretical and experimental study of the detailed
frequency dependence of the ''ionization'' of excited H atoms by a tw
o-frequency (2f) microwave field. Our ID quantal and 1D classical calc
ulations, in excellent agreement with each other, predict a new 2f ion
ization peak. The peak scales classically. We present a model which sh
ows that the location and the width of the peak are determined by clas
sical phase-space structures. The theoretical results are supported by
experimental data with 3D atoms.