Enhanced ionization of the H2 molecule driven by intense ultrashort laser pulses

We report correlated two-electron ab initio calculations for the hydrogen molecule H-2 in interaction with intense ultrashort laser pulses, via a solution of the full three-dimensional time-dependent Schrodinger equation. Our results for ionization and excitation probabilities (at 800 and 400 nm) as a function of internuclear distance R show strong evidence of enhanced ionization, in both single and double ionization, as well as enhanced excitation, in single and double excitation, as the internuclear distance R increases from the equilibrium value R-e. The enhancement of all these molecular processes exhibits a maximum at a critical distance R-c, which can be predicted from simple electrostatic and recollision models.