Heidelberg 1999 – scientific programme

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A: Atomphysik

A 16: Atome in äußeren Feldern

A 16.3: Talk

Friday, March 19, 1999, 14:45–15:00, TE4

Atomic Resonances in External Fields — •R. González-Férez and W. Schweizer — Theoretische Astrophysik Tuebingen

The states of an atom in external electric fields become quasi-bound since the electron can ionize by tunnelling through the potential barrier into the continuum. These resonance states can be studied using the complex coordinate method. In this method the Hamiltonian of the system is continued into the complex plane by a complex dilatation, therefore the Hamiltonian is no longer hermitian and can support complex eigenenergies associated with decaying states. The basic idea is to combine this complex coordinate rotation method with the finite element method, and the discrete variable technique. We get a complex symmetric Hamiltonian matrix, which we solve using the implicitly restarted Arnoldi method (ARPACK). These methods have been extended to alkali atoms in external strong magnetic and electric field by including model potentials.