1996-01-01

# Two-electron atoms in superintense radiation fields: Dichotomy and stabilization

## Publication

### Publication

*Phys. Rev. A , Volume 53 p. 3431- 3443*

The high-frequency Floquet theory describing the interaction of a two-electron atom with a linearly polarized laser field is applied to the case when the characteristic parameter *a*_{0}=E_{0}*w*^{-2} a.u. is large, corresponding to the dichotomy regime of the one-electron problem. We first revisit this case and extend the large- *a*_{0} energy-level formula obtained earlier to higher order in* a*_{0}^{-1}. We then prove the existence of a dichotomy regime also for the two-electron atom, characterized by the two electrons being situated in disjoint electronic clouds separated by an average distance of 2*a*_{0}. We obtain the first four terms in the expansion of the related energy-level formula in fractional powers of *a*_{0}^{-1}. The coefficients entering this expansion have been expressed in terms of the eigenvalues of a nonseparable Schrödinger equation containing the end-point potential and of integrals over its eigenfunctions. The equation was solved using the finite element method. An infinite sequence of levels emerges. In the case of H^{-} this implies the existence of a large number of light-induced excited states, some of them corresponding to two-electron excitations not subject to autodetachment. Finally, we prove that in the dichotomy regime a two-electron atom undergoes stabilization and that the ionization rates are essentially twice those for a one-electron atom with the same nuclear charge.

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Journal | Phys. Rev. A |

Citation |
Gavrila, M, & Shertzer, J. (1996). Two-electron atoms in superintense radiation fields: Dichotomy and stabilization.
Phys. Rev. A, 53, 3431–3443. |