Back-to-back emission of the electrons in double photoionization of helium
M. Ya. Amusia+*, E. G. Drukarev+×, E. Z. Liverts+
+The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
*Ioffe Physico-Technical Institute, 194021 St.Petersburg, Russia
×Konstantinov Petersburg Institute of Nuclear Physics, 188300 Gatchina, Russia
Abstract
We calculate the double differential distributions and
distributions in recoil momenta for the high energy non-relativistic double
photoionization of helium atom. We show that the results of recent
experiments provide the pioneering experimental manifestation of the
quasifree mechanism for the double photoionization which was predicted long
ago in our papers. This mechanism provides a surplus in distribution over the
recoil momenta at small values of the latter, corresponding to nearly
"back-to-back" emission of the photoelectrons. Also, in agreement with
previous analysis we demonstrate that this surplus is due to the quadrupole
terms of the photon-electron interaction. We present the characteristic
angular distribution for the "back-to-back" electron emission. The
confirmation of the quasifree mechanism existence opens a new area for
exciting experiments, which are expected to increase our understanding of the
electron dynamics and of the bound states structure.