Enhanced Ionization of Linear Polyatomic Molecular Ions in Ultrashort Laser Fields

The ionization behavior of linear polyatomic molecular ions in ultrashort, intense laser fields was investigated with the time-dependent Schrödinger equation solved by the standard split-operator algorithm. The enhanced ionization effect was found as a general feature in the ions when the internuclear separation was in a critical distance range and can be explained in terms of the field-induced over-barrier ionization mechanism. In addition, the ionization energy does not influence the ionization probability significantly.