Mangan, TP, Frankland, VL, Murray, BJ et al. (1 more author) (2017) The fate of meteoric metals in ice particles: Effects of sublimation and energetic particle bombardment. Journal of Atmospheric and Solar-Terrestrial Physics, 161. pp. 143-149. ISSN 1364-6826
Abstract
The uptake and potential reactivity of metal atoms on water ice can be an important process in planetary atmospheres and on icy bodies in the interplanetary and interstellar medium. For instance, metal atom uptake affects the gas-phase chemistry of the Earth’s mesosphere, and has been proposed to influence the agglomeration of matter into planets in protoplanetary disks. In this study the fate of Mg and K atoms, incorporated into water-ice films prepared under ultra-high vacuum conditions at temperatures of 110–140 K, was investigated. Temperature-programmed desorption experiments reveal that Mg- and K-containing species do not co-desorb when the ice sublimates, demonstrating that uptake on ice particles causes irreversible removal of the metals from the gas phase. This implies that uptake on ice particles in terrestrial polar mesospheric clouds accelerates the formation of large meteoric smoke particles (≥1 nm radius above 80 km) following sublimation of the ice. Energetic sputtering of metal-dosed ice layers by 500 eV Ar+ and Kr+ ions shows that whereas K reacts on (or within) the ice surface to form KOH, adsorbed Mg atoms are chemically inert. These experimental results are consistent with electronic structure calculations of the metals bound to an ice surface, where theoretical adsorption energies on ice are calculated to be −68 kJ mol−1 for K, −91 kJ mol−1 for Mg, and −306 kJ mol−1 for Fe. K can also insert into a surface H2O to produce KOH and a dangling H atom, in a reaction that is slightly exothermic.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2017 Elsevier Ltd. This is an author produced version of a paper published in Journal of Atmospheric and Solar-Terrestrial Physics. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Polar mesospheric clouds; Meteoric metals; Meteoric smoke particles; Energetic particle bombardment |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) |
Funding Information: | Funder Grant number EU - European Union 291332 EU - European Union 648661 |
Depositing User: | Symplectic Publications |
Date Deposited: | 11 Jul 2017 15:43 |
Last Modified: | 08 Jul 2018 00:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.jastp.2017.07.002 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:118951 |