Nuclear wave-packet dynamics in triatomic molecules

We theoretically investigate pump-probe dissociative ionization of triatomic molecules by propagating the coupled nuclear motion on potential energy surfaces, including all vibronic degrees of freedom (symmetric stretch, bending, and antisymmetric stretch modes). We calculate potential energy surfaces, diabatic couplings, and laser-induced dipole couplings ab initio using the multi-configurational self-consistent field  quantum-chemistry code GAMESS [1]. In particular, we reveal the imprints of the dynamics near a conical intersection in CO₂⁺ [1] and coherent bending vibrations in SO₂⁺ [2] on measured, pump-probe delay-dependent fragment kinetic energy spectra. Our simulated data is in good agreement with the experimental data [1,2].