Vibrationally Dependent Stereodynamic Control of Scattering Resonances in Cold CO + H ₂ Collisions

Cold molecules provide a unique platform for exploring quantum phenomena. Using the Stark-induced adiabatic Raman passage (SARP) technique, it has, for example, been demonstrated that resonances are sensitive to the initial orientation/alignment of collisional partners at low collision temperatures. In this work, we investigate the stereodynamics of the following rotationally inelastic collision process through full-dimensional quantum scattering calculations, CO (<i>v</i>₁ = 0, <i>j</i>₁ = 0) + H₂ (<i>v</i>₂, <i>j</i>₂ = 2) → CO (<i>v</i>₁^' = 0, <i>j</i>₁^' = 0) + H₂ (<i>v</i>₂^' = <i>v</i>₂, <i>j</i>₂^' = 0), focusing on its dependence on vibrational excitation of a collision partner (<i>v</i>₂). The integral cross-section is shown to be overall vibrationally adiabatic with a slight red shift of 1 cm^-1 per <i>v</i>₂ for the four main resonance peaks but with irregular relative scattering amplitudes. The horizontal SARP induces completely different effects on cross-sections for one of the resonances between different vibrational states: a 92.2% suppression for <i>v</i>₂ = 0 versus a 120.7% enhancement for <i>v</i>₂ = 1. Our findings establish vibrational-state-selective engineering as a potential paradigm for cold collision control.