IONIZATION OF ATOMS IN ELECTRIC AND MAGNETIC-FIELDS AND THE IMAGINARYTIME METHOD

A semiclassical theory is developed for the ionization of atoms and ne gative ions in constant, uniform electric and magnetic fields, includi ng the Coulomb interaction between the electron and the atomic core du ring tunneling. The case of crossed fields (Lorentz ionization) is exa mined specially, as well as the limit of a strong magnetic field. Anal ytic equations are derived for arbitrary fields E and H that are weak compared to the characteristic intraatomic fields. The major results o f this paper are obtained using the ''imaginary time'' method (ITM), i n which tunneling is described using the classical equations of motion but with purely imaginary ''time.'' The possibility of generalizing t he ITM to the relativistic case, as well as to states with nonzero ang ular momentum, is pointed out. (C) 1998 American Institute of Physics. [S1063-7761(98)00405-3].