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

ABSTRACT

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 $v_0$ with inner radius $r_0$ and thickness Δ 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.

GRAPHICAL ABSTRACT

KEYWORDS:

• Confined atoms
• ionisation probability
• sudden approximation

Acknowledgements

A.S. would like to thank Dra. M${}^{\mathrm{a}}$ Pilar de Lara Castells for many fruitful discussions and encouraging conversations during the realisation of this and other works.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Antonio Sarsa  http://orcid.org/0000-0002-7123-4598

Additional information

Funding

This work was partially supported by the Spanish Dirección General de Investigación Científica y Técnica (DGICYT) and FEDER under contract FIS2015-69941-C2-2-P and the Junta de Andalucía under grant FQM378. The work of M.F.M. was partially supported by a Ph.D. fellowship from Spanish Ministerio de Ciencia, Innovación y Universidades under grant FPU16/05950. The work of A.S. was partially supported by the COST Action MOLIM CM1405.