Comparison of ADK ionization rates as a diagnostic for selective vibrational level population measurement

We have used a wavefunction-modified Ammosov-Delone-Krainov (ADK) method to calculate the ionization rates of H-2, N-2 and CO2 as a function of initial vibrational level of the molecules. A strong increase in the ionization rate, with vibrational level, is found for H-2, while N-2 and CO2 show a lesser increase. We have also compared the enhancement ratios between the ground and excited vibrational levels obtained from (1) a focal-volume averaged ADK procedure and (2) simple over-the-barrier calculations, and found dramatic differences in ionization dependence on vibrational levels for the different molecules.