AUTHOR=Upadhyay Meenu , Meuwly Markus 

TITLE=Energy Redistribution Following CO2 Formation on Cold Amorphous Solid Water

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 9 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.827085

DOI=10.3389/fchem.2021.827085

ISSN=2296-2646

ABSTRACT=The formation of molecules in and on amorphous solid water (ASW) as it
occurs in interstellar space releases appreciable amounts of energy
that need to be dissipated to the environment. Here, energy transfer
between CO$_2$ formed within and on the surface of amorphous solid
water (ASW) and the surrounding water is studied. Following CO($^1
\Sigma^+$) + O($^1$D) recombination the average translational and
internal energy of the water molecules increases on the $\sim 10$ ps
time scale by 15 \% to 20 \% depending on whether the reaction takes
place on the surface or in an internal cavity of ASW. Due to tight
coupling between CO$_2$ and the surrounding water molecules the
internal energy exhibits a peak at early times which is present for
recombination on the surface but absent for the process inside
ASW. Energy transfer to the water molecules is characterized by a
rapid $\sim 10$ ps and a considerably slower $\sim 1$ ns
component. Within 50 ps a mostly uniform temperature increase of the
ASW across the entire surface is found. The results suggest that
energy transfer between a molecule formed on and within ASW is
efficient and helps to stabilize the products generated.