Effects of pulse duration and wavelength on the nonsequential ionization of helium

Lappas, D. G.; Corso, P. P.; Knight, P. L.
July 2000
AIP Conference Proceedings;2000, Vol. 525 Issue 1, p245
Academic Journal
We report calculations of the ionization yields of a model one-dimensional He atom in strong and short laser pulses. We use both an exact fully correlated two-electron scheme and an approximate model known as “crapola”. For a wide range of frequencies, from 248 nm to 1064 nm, we find a significant signal for nonsequential double ionization. The duration of the laser pulse is shown to have an observable effect on the well known “knee” structure of the double ionization yields. Our model calculations allow us to probe the mechanism of the correlated two electron ejection. We find that the shake-off mechanism appears to be insignificant, at least in the wavelength regime that is considered in this work. Evidence for a periodic rescattering mechanism is presented. © 2000 American Institute of Physics.


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