Multidimensional Mesh Approaches to Calculations of Atoms and Diatomic Molecules in Strong Electric Fields

摘要

Fully numerical mesh solutions of 2D and 3D quantum equations of Schroedingerand Hartree-Fock type allow us to work with wavefunctions which possess a veryflexible geometry. This flexibility is especially important for calculations ofatoms and molecules in strong external fields where neither the external fieldnor the internal interactions can be considered as a perturbation. In theframework of this method we present various approaches to calculations ofquasi-steady states of these systems in strong electric fields. Theseapproaches are aimed at obtaining precise complex wavefunctions andcorresponding eigenvalues in the form E = E_0 - i\Gamma/2, where E_0 is thereal part of the energy and the value \Gamma/2 determines the lifetime of thestate in relation to escape of electrons from the system. The applications forsingle-electron systems include correct solutions of the Schroedinger equationfor the H_2^+ ion (energies and decay rates) and the hydrogen atom in strongparallel electric and magnetic fields. Some results for the helium atom instrong electric fields are announced.