In this paper we calculated the model dependence of the field ionization rate of hydrogen atom in a uniform electric field. In order to calculate the probability of barrier penetration we use semiclassical (WKB) approximation, which is calculated for two model potentials. In the model 1 the Coulomb potential is used only near the nucleus. In model 2 the Coulomb potential is used in all regions. These results are compared with the accepted result of 4F -1 exp (-2/3F ).
field ionization; tunnel effect; WKB approximation
