Non-universal quantum dynamics of the ultracold chemical reaction for Li+NaLi(³Σ⁺) → Li₂ (³Σ_u⁺)+Na

In a theoretical study of ultracold barrierless chemical reactions between spin-polarized NaLi molecules and Li atoms, we find strong signatures of non-universal reaction dynamics. Specifically, we observe a large sensitivity of the total reaction rate coefficient to small variations in the short-range non-additive three-body potential of the spin-polarized NaLi₂ (⁴A) reaction complex. The sensitivity occurs despite the presence of a deep attractive well in the ab initio PES of the complex. We attribute the origin of this effect to the relatively small number of open reaction channels. In other words, short-range interactions in reaction complexes can be effectively probed via ultracold reactive scattering experiments that measure total reaction rates.