Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-27T09:36:33.674Z Has data issue: false hasContentIssue false

Monte Carlo Modeling of Astrophysically-Relevant Temperature-Programmed Desorption Experiments

Published online by Cambridge University Press:  04 September 2018

Aspen R. Clements
Affiliation:
Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, VA 22904-4319 email: ac8hq@virginia.edu
Ilsa Cooke
Affiliation:
Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, VA 22904-4319 email: ac8hq@virginia.edu
Robin T. Garrod
Affiliation:
Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, VA 22904-4319 email: ac8hq@virginia.edu Department of Astronomy, University of Virginia, P.O. Box 400325 Charlottesville, VA 22904-4325
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The formation of molecules in the interstellar medium is significantly driven by grain chemistry, ranging from simple (e.g. H2) to relatively complex (e.g. CH3OH) products. The movement of atoms and molecules on amorphous ice surfaces is not well constrained, and this is a quintessential component of surface chemistry. We show that ice structure created by utilizing an off-lattice Monte Carlo kinetics model is highly dependent on deposition parameters (i.e. angle, rate, and temperature). The model, thus far, successfully predicts the densities of deposition rate- and temperature-dependent laboratory experiments. The simulations indicate, when angle and deposition rate increase, the density decreases. On the other hand, temperature has the opposite effect and will increase the density. We can make ices with desired densities and monitor how molecules, like CO, percolate through H2O ice pores. The strength of this model lies in the ability to replicate TPD-like experiments by monitoring molecules diffusing on and desorbing from user-defined surfaces.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2018 

References

Ayotte, P., Smith, R. S., Stevenson, K. P., et al., 2001, JGR, 106, 33, 387-33, 392Google Scholar
Boogert, A. C. A., Gerakines, P. A., & Whittet, D. C. B., 2010, ARAA, 53, 541581Google Scholar
Collings, M. P., Dever, J. W., Fraser, H. J., et al. 2002, ApJ, 583, 10581062Google Scholar
Collings, M. P., Anderson, M. A., Chen, R., et al., 2004, MNRAS, 354, 1133Google Scholar
Cuppen, H. M. & Herbst, E., 2005, MNRAS, 361, 565576Google Scholar
Fayolle, E. C., Balfe, J., Loomis, R., et al. 2016, ApJL, 816:L28, 6ppGoogle Scholar
Garrod, R. T., 2013, ApJ, 151, 158Google Scholar
Gibb, E. L., Whittet, D. C. B., Boogertand, A. C. A., et al., 2004, ApJ, 778, 3574Google Scholar
Hidaka, H., Miyauchi, N., Kouchi, A., & Watanabe, N., 2008, CPL, 456, 3640Google Scholar
Oberg, K. I., Boogert, A. C. A., Pontoppidan, K. M., et al., 2011, ApJ, 740, 6578Google Scholar