Enhanced ionization of perpendicularly aligned H2 in intense laser fields

Using three-dimensional classical ensembles, we have investigated the enhancement of double ionization of perpendicularly aligned H2 molecules by a 800 nm laser pulse with intensity ranging from 1 × 1014 W/cm2 to 6 × 1014 W/cm2. The simulated results show that double ionization probability of H2 strongly depends on R and reaches a maximum at an intensity independent critical distance RC ≈ 5 a.u. Furthermore, the enhancement of double ionization is more pronounced in the cases of weaker or stronger fields. These results, a well indication of the influence of molecular structures and laser–molecule interactions on double ionization of diatomic molecules, are analyzed in detail and qualitatively explained based on the field-induced barrier suppression model and back analysis.

Research Highlights► The pronouncement of enhanced ionization of H2 changes with laser intensity. ► We present the critical distance double ionization of perpenducularly aligned H2. ► The critical distance of perpenducularly aligned H2 is intensity independent. ► We explain our results by barrier suppression model and back analysis.