Relativistic Theory of Tunnel Ionization of an Atom in Parallel Electric and Magnetic Fields

Abstract

The method of quasiclassical localized states is developed for the stationary Dirac equation with an arbitrary axially symmetrical electric potential of barrier type and potential of uniform magnetic field directed along the symmetry axis. Using this method quasiclassical wavefunctions for an arbitrary relativistic atom in the parallel uniform electric and magnetic fields are constructed in classically forbidden and allowed regions. The general analytical expressions for leading term of the asymptotic (in intensities of electrostatic F and magnetic H fields) behaviour of ionization rate of an atom and negative ion in such electromagnetic field are found. Various limiting cases of the expression obtained are analyzed.