Threshold energy and angular distributions in multiple ionization

The Wannier theory for double escape near threshold (1965) makes detailed predictions for the energy and angular distributions of the outgoing electrons. Not only the dependence on the excess energy above threshold but even the numerical coefficient in front that governs these distributions can be derived as a function of the charge Z on the residual core. These are of interest with the advent of recent accurate experiments and computer calculations. Such coefficients are presented and it is pointed out that there is a dramatic disappearance of some correlations for Z\u3eor=3. Recent computer calculations for Z=2 can, perhaps, be extended to verify this result. Similar non-monotonic dependences on Z are to be expected for triple and other multiple escape