2024A&A...688A.140I

We modeled the collisions between OH⁺ projectiles with kinetic energies ranging from 10 to 22 eV and an amorphous cold (CH₃OH)₁₀ substrate using Born-Oppenheimer molecular dynamics (BOMD) simulations. We conducted the simulations for a collision time of 400 femtoseconds (fs), during which we followed multiple bond-forming and breaking reactions. Here, we report four new pathways for the formation of formic acid HCOOH. We find new precursors such as CH₃(OH)$ _2^{+} $ , HC(OH)$ _2^{+} $ , CH₂OH⁺, and CH₂(OH)₂, which are essential in these pathways for the formation of formic acid. The methanodiol CH₂(OH)₂ and hydroxymethyl CH₂OH⁺ cations have previously been identified as key precursors of formaldehyde. These pathways suggest new ways to form formic acid in methanol ice mantles on dust grains, offering alternative mechanisms leading to the formation of complex organic molecules (COMs) in space.