The steric effect in the formation of protonated HCOOH

We explore from a theoretical perspective the steric effect in the collision dynamics of proton to formic acid at 2 eV by a time-dependent local-density approximation for valence electrons, coupled to molecular dynamics for the ionic cores. Eight specific collision configurations are taken into consider. We find that at this low impact energy, protonation is the dominant reaction channel. There are two forms of protonation-formation induced by steric effect: 1,3-intramolecular H shift and out-of-plane oscillation.