Journal of Physical Chemistry A, Vol.111, No.38, 9340-9346, 2007
Multiphoton ion pair spectroscopy (MPIPS) with ultrashort laser pulses for the H-2 molecule
Time-dependent Schrodinger equation, TDSE, simulations have been performed in order to prepare and study via MPIPS the evolution of vibrational wave packets on the ion pair electronic state potentials B ''(B) over bar (1)Sigma(+)(u) and H (H) over bar (1)Sigma(+)(g) of the H-2 molecule. Using ab initio potential surfaces and transition moments, we present two- and three-photon excitation schemes with ultrashort pulses (tau <= 10 fs) to prepare coherent superpositions of the two ion pair H+H- and H-H+ states from the doorway B-1 Sigma(+)(u) state, which result from the strong radiative coupling between these two electronic states. The simulations are used to estimate the time evolution and u recursion times of vibrational wave packets at large internuclear distances, usually not accessible by single-photon spectroscopy. Conditions for the localization of the ion pair states are proposed.