Ionization of a model atom by a pulse of coherent radiation

Abstract

The time evolution of the ionization probability of a simple one-dimensional model atom under the influence of a harmonic electric field is studied by the numerical solution of the time-dependent Schrodinger equation. The conditions are clarified under which tunnelling or multiphoton absorption may be regarded as appropriate mechanisms. The standard tunnelling formulae are found to give poor quantitative estimates of ionization probability. The duration of the radiation pulse is found to be of critical importance, as multiphoton absorption is seen to require a certain minimum time to develop.