Ionisation and excitation probabilities of a hydrogen atom suddenly released from penetrable confinement

The problem of the stability of the hydrogen atom when it is released from a confining environment is studied. The stability is analysed in terms of excitation and ionisation probabilities of the final state for different initial states. A spherical confining cavity of finite barrier height with inner radius and thickness with the nuclear position at its centre has been considered. The ionisation probability presents different sharply peaked, non-symmetric local maxima as a function of the confinement size. This behaviour is related to the energy of the initial confined state that presents several maxima and minima in a kink-like structure as a function of the confinement size. The physical origin of these effects has been explained in terms of tunnelling and re-tunnelling of the atomic states. The sudden approximation and the analytic continuation method have been employed. [GRAPHICS] .