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Dynamics of CO in Amorphous Water-ice Environments

Karssemeijer, L. J. and Ioppolo, S. and van Hemert, M. C. and van der Avoird, A. and Allodi, M. A. and Blake, G. A. and Cuppen, H. M. (2014) Dynamics of CO in Amorphous Water-ice Environments. Astrophysical Journal, 781 (1). Art. No. 16. ISSN 0004-637X.

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The long-timescale behavior of adsorbed carbon monoxide on the surface of amorphous water ice is studied under dense cloud conditions by means of off-lattice, on-the-fly, kinetic Monte Carlo simulations. It is found that the CO mobility is strongly influenced by the morphology of the ice substrate. Nanopores on the surface provide strong binding sites, which can effectively immobilize the adsorbates at low coverage. As the coverage increases, these strong binding sites are gradually occupied leaving a number of admolecules with the ability to diffuse over the surface. Binding energies and the energy barrier for diffusion are extracted for various coverages. Additionally, the mobility of CO is determined from isothermal desorption experiments. Reasonable agreement on the diffusivity of CO is found with the simulations. Analysis of the 2152 cm^−1 polar CO band supports the computational findings that the pores in the water ice provide the strongest binding sites and dominate diffusion at low temperatures.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ioppolo, S.0000-0002-2271-1781
Allodi, M. A.0000-0002-3289-1659
Blake, G. A.0000-0003-0787-1610
Additional Information:© 2014 American Astronomical Society. Received 2013 October 15; accepted 2013 November 25; published 2013 December 30. We gratefully acknowledge A. Pedersen for valuable help with the EON code and P. Theule for stimulating discussions. This work has been funded by the European Research Council (ERC-2010-StG, grant agreement No. 259510-KISMOL), the VIDI research programme 700.10.427, financed by The Netherlands Organization for Scientific Research (NWO), the National Science Foundation CRIF:ID andCSDMprograms and the NASA Exobiology and Laboratory Astrophysics programs. M.A.A was supported by the Department of Defense (DoD) Air Force Office of Scientific Research, National Defense Science and Engineering Graduate (NDSEG) Fellowship, 32 CFR 168a. S.I. acknowledges support from a Niels Stensen Fellowship and a Marie Curie Fellowship (FP7-PEOPLE-2011-IOF-300957). L.J. Karssemeijer thanks COST Action Number CM0805 (The Chemical Cosmos: Understanding Chemistry in Astronomical Environments) for funding of several stimulating conferences and collaboration visits.
Funding AgencyGrant Number
European Research Council (ERC)259510-KISMOL
Netherlands Organization for Scientific Research (NWO) VIDI research programme700.10.427
Air Force Office of Scientific Research (AFOSR)UNSPECIFIED
National Defense Science and Engineering Graduate (NDSEG) Fellowship32 CFR 168a
Niels Stensen FellowshipUNSPECIFIED
Marie Curie FellowshipFP7-PEOPLE-2011-IOF-300957
COST ActionCM0805
Subject Keywords:astrochemistry; diffusion; ISM: clouds; methods: laboratory: molecular; methods: numerical; molecular processes
Issue or Number:1
Record Number:CaltechAUTHORS:20140210-115650052
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Official Citation:Dynamics of CO in Amorphous Water-ice Environments L. J. Karssemeijer et al. 2014 ApJ 781 16
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43745
Deposited By: Jason Perez
Deposited On:11 Feb 2014 00:06
Last Modified:09 Mar 2020 13:18

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