THE TUNNEL IONIZATION OF ATOMS, DIATOMIC AND TRIATOMIC-MOLECULES USING INTENSE 10.6 MU-M RADIATION

A broad collection of experimental tunnel ionization data, obtained us ing intense 10.6 mum CO2 laser radiation, is presented. The variety of species studied includes three rare gas atoms (Xe, Kr and Ar), three homonuclear diatomic molecules (H-2, O2 and N2), two heteropolar diato mic gases (CO and NO) and one triatomic molecule (CO2). The ionization behaviour going from the neutral particle to its associated singly ch arged ionic state, for all of the above species, is compared with a qu asistatic tunnel ionization model. Good agreement between this theoret ical model and the complete range of experimental results is found.