| The photoionization cross section of helium shows chaotic signals, of which fluctuating part decreases in amplitude as the energy approaches the double ionization threshold from below. The fluctuations were interpreted as associated with the closed triple collision orbits, and a scaling law for the energy-dependence of the amplitude of fluctuating part was suggested by applying a semiclassical approximation to the Green's function for the closed triple collision orbits. We will present results of quantum calculation of the total and partial photo-ionization cross sections of the helium atom, comparing our numerical results with an experimental results obtained by Jiang et al and demonstrating the scaling law. |
|