Quantum mechanical simulation of the dissociation dynamics of the N$_{2}$ (N$_{2}^{+}$, N$_{2}^{++})$ and O$_{2}$ (O$_{2}^{+}$, O$_{2}^{++})$ molecules*

The nuclear dynamics of molecular nitrogen and oxygen in intense laser fields was studied by analyzing their fragment kinetic energy release (KER) spectra as a function of time$^{1}$. Typically, several intermediate states contribute to the same KER. Based on a quantum mechanical model, we calculated the time evolution of an initial (ground state) nuclear wave packet in N$_{2}^{+}$ and N$_{2}^{++}$ (O$_{2}^{+}$ and O$_{2}^{++})$ separately, for given adiabatic molecular potential curves, in order to assess the relevance of individual potential curves during the laser-induced fragmentation. By Fourier transformation of the nuclear probability density with respect to time, we derive internuclear distance (R) dependent power spectra$^{2}$ that allow us to identify vibrational frequencies associated with the bound motion of the vibrationally excited molecular ion. To include laser-induced dynamical couplings between molecular potential curves we are in the process of modeling (non)adiabatic transitions near curve crossings based on Landau-Zener transition rates and will compare our numerical results with existing measured KER- spectra. $^{1}$I. Bocharova et al., to be published. $^{2}$M. Magrakvelidze et al., PRA 79, 033410 (2009) *Supported by the US DOE.