Perpendicular dissociation ofD2+in intense Ti:sapphire laser pulses

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Detailed results of numerical one-dimensional wave-packet simulations are reported for the dynamics of a ${\mathrm{D}}_{2}^{+}$ molecule subjected to separated and combined 400-nm and 800-nm intense laser pulses with their polarization vectors lying either parallel or perpendicular to the internuclear axis of the molecule. Depending on the laser excitation conditions, the model employed involves from four to a maximum of eight electronic channels, comprising molecular states correlating, in the dissociative limit, with the $n=1$ shell of atomic hydrogen and those correlating with the $n=2$ shell. Preliminary results of calculations including molecular rotations within a two-dimensional model are also reported. Overall, calculated fragment kinetic-energy spectra, the main results of the present work, are in accord with the findings of recent experimental works [Talebpour et al., Phys. Rev. A 62, 042708 (2000); Vijayalakshmi et al., ibid. 053408 (2000)], which reported evidences of perpendicular dissociation induced by intense 400-nm and 800-nm laser pulses. These results are thus supportive of the hypothesis made therein of perpendicular transitions to upper molecular excited states, through a ${\ensuremath{\pi}}_{u}$ doorway. Deviations from the predictions of the Floquet schemes proposed in these works are discussed in terms of the laser-driven rotational dynamics of the molecular ion and in terms of bond-softening versus bond-hardening effects.