Neural-Network Assisted Study of Nitrogen Atom Dynamics on Amorphous
  Solid Water. I. Adsorption & Desorption
  Dynamics of adsorption and desorption of (4S)-N on amorphous solid water are
analyzed using molecular dynamics simulations. The underlying potential energy
surface was provided by machine-learned interatomic potentials. Binding
energies confirm the latest available theoretical and experimental results. The
nitrogen sticking coefficient is close to unity at dust temperatures of 10 K
but decreases at higher temperatures. We estimate a desorption time scale of 1
{\mu}s at 28 K. The estimated time scale allows chemical processes mediated by
diffusion to happen before desorption, even at higher temperatures. We found
that the energy dissipation process after a sticking event happens on the
picosecond timescale at dust temperatures of 10 K, even for high energies of
the incoming adsorbate. Our approach allows the simulation of large systems for
reasonable time scales at an affordable computational cost and ab-initio
accuracy. Moreover, it is generally applicable for the study of adsorption
dynamics of interstellar radicals on dust surfaces.
