TUNNELING IONIZATION OF ATOMIC-HYDROGEN BY AN INTENSE LOW-FREQUENCY FIELD

We present results of Floquet calculations of rates for ionization of H by high-intensity light with wavelengths up to 1064 nm. If the frequency is well below the atomic-orbital frequency at the rates approximately obey a law similar to that given by the Keldysh tunneling theory, and they approach the dc rate as the intensity increases. If >at there is no tunneling regime and the rates eventually decrease toward zero as the intensity increases. © 1990 The American Physical Society.