Ammonia clathrate hydrates as new solid phases for Titan, Enceladus, and other planetary systems
- 20 August 2012
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 109 (37), 14785-14790
- https://doi.org/10.1073/pnas.1205820109
Abstract
There is interest in the role of ammonia on Saturn's moons Titan and Enceladus as the presence of water, methane, and ammonia under temperature and pressure conditions of the surface and interior make these moons rich environments for the study of phases formed by these materials. Ammonia is known to form solid hemi-, mono-, and dihydrate crystal phases under conditions consistent with the surface of Titan and Enceladus, but has also been assigned a role as water-ice antifreeze and methane hydrate inhibitor which is thought to contribute to the outgassing of methane clathrate hydrates into these moons' atmospheres. Here we show, through direct synthesis from solution and vapor deposition experiments under conditions consistent with extraterrestrial planetary atmospheres, that ammonia forms clathrate hydrates and participates synergistically in clathrate hydrate formation in the presence of methane gas at low temperatures. The binary structure II tetrahydrofuran + ammonia, structure I ammonia, and binary structure I ammonia + methane clathrate hydrate phases synthesized have been characterized by X-ray diffraction, molecular dynamics simulation, and Raman spectroscopy methods.Keywords
This publication has 39 references indexed in Scilit:
- Is Titan's shape caused by its meteorology and carbon cycle?Geophysical Research Letters, 2012
- Stability of methane clathrate hydrates under pressure: Influence on outgassing processes of methane on TitanIcarus, 2009
- Ammonium sulfate on Titan: Possible origin and role in cryovolcanismIcarus, 2007
- Episodic outgassing as the origin of atmospheric methane on TitanNature, 2006
- Mid-infrared characterization of the NH4+∙(H2O)n clusters in the neighborhood of the n=20 “magic” numberThe Journal of Chemical Physics, 2005
- The structure, ordering and equation of state of ammonia dihydrate (nh3 · 2h2o)Icarus, 2003
- Hydrogen Bond Surface Chemistry: Interaction of NH3 with an Ice ParticleThe Journal of Physical Chemistry B, 2000
- Rate Study of Ice Particle Conversion to Ammonia Hemihydrate: Hydrate Crust Nucleation and NH3 DiffusionThe Journal of Physical Chemistry A, 2000
- Coated Ice Nanocrystals from Water−Adsorbate Vapor Mixtures: Formation of Ether−CO2 Clathrate Hydrate Nanocrystals at 120 KThe Journal of Physical Chemistry B, 1998
- A Clathrate Hydrate of FormaldehydeThe Journal of Physical Chemistry, 1996