Full quantum time-dependent simulations for the two-body breakups of H2Ar2+ and N2Ar2+

We developed a full quantum time-dependent wave-packet evolution method to simulate the multibody breakups of polyatomic molecular ions. The interaction picture theory was used to propagate the wave packet, where the effects of strong and long-range interactions are considered by basis functions and the weak and short-range interactions are included in the perturbation term. In this method, the Coulomb interactions, polycentric interactions, vibration-rotation coupling of molecular fragments, and the rotation-rotation coupling between molecular fragment and parent molecule are considered accurately. Using this method, we simulate the two-body breakups of H2Ar2+ and N2Ar2+. The simulated results show that the ultrafast rotation of the molecular fragment generally exists in the breakup of the polyatomic molecular ion. For H2Ar2+, H-2(+) can rotate from an initial broad distribution around 35 degrees and 145 degrees to a narrow distribution around 75 degrees and 105 degrees within 30 fs. For N2Ar2+, the initial sine-shaped angular distribution (j = 0) shrinks to a narrow range (90 degrees +/- 20 degrees) within 120 fs and then spreads to an approximately random distribution within 300 fs. Such ultrafast rotations are dominated by the polycentric interaction between fragments and impacted by the vibration-rotation and rotation-rotation couplings.

Automated summary

In this study, a quantum time-dependent wave-packet evolution method was developed to simulate the multibody breakups of polyatomic molecular ions. The results show that ultrafast rotations of molecular fragments occur during the breakup process, and these rotations are influenced by various interactions such as polycentric interaction and vibration-rotation/rotation-rotation couplings.