On the formation of molecules through direct three-body recombination: the effect of long-range interactions

We present a study on the role of the long-range tail of pairwise interactions in neutral-neutral-neutral and ion-neutral-neutral direct three-body recombination processes based on a classical trajectory method in hyperspherical coordinates [J. Chem. Phys. 140, 044307 (2014)]. In particular, we focus on the formation of van der Waals molecules X-RG (where RG is a rare gas atom) via X+ RG + RG→X-RG + RG collisions at temperatures relevant for buffer gas cells [J. Chem. Phys. 154, 034305 (2021)], and the formation of molecular ions at low temperatures. As a result, we show that almost any X-RG molecule should appear in a buffer gas cell under appropriate conditions. Furthermore, we investigate the previously derived threshold laws for ion-neutral-neutral systems [J. Chem. Phys. 143, 041105 (2015)] via a systematic method in hyperspherical coordinates.