Validity of the Wannier threshold law for angular correlation width in double photoionization of atoms

Hybrid surface-flux method for extraction of the ionization amplitude from the calculated wave function

“…On the contrary, in the two-body problems such as the helium double photoionization [16] the wavefunction on the boundary is revealed as the superposition of the states describing either the double photoionization as well as the single ionization with one electron remained bound in a number of the residual ion excited states. The latter have substantionally different energies, as a result |ψ(r S , t)| even at very large t values does not tend monotonically to zero, but instead oscillates in a complicated fashion, so that the approximation (17) becomes invalid, and under the effective energy evaluation via the relation (18) the ℑE ef f periodically takes the positive values. Among other things, this particularity complelled us after the attempts of the t-SURFFc utilizing to employ [16] the approach for the double ionization amplitude exctraction.…”

“…Finally, McCurdy et al have suggested an approach rest upon the evaluation of the flux of the probability amplitude for the scattering function derived by the Green's function operator action to the wavefunction after the end of the pulse [13,14] (in what follows we will refer to this method as the E-SURFF). The drastic solution to the problem under consideration is the utilizing of the time-dependent scaling approach [15][16][17][18][19].…”