Astronomy and Astrophysics – Astronomy
Scientific paper
Oct 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007dps....39.3804s&link_type=abstract
American Astronomical Society, DPS meeting #39, #38.04; Bulletin of the American Astronomical Society, Vol. 39, p.489
Astronomy and Astrophysics
Astronomy
Scientific paper
The condensed O2 found on Ganymede and Europa, and its relationship to tenuous O2 atmospheres have long been a puzzle considering the instability of solid oxygen at the relative high temperatures of the satellites. We report on the discovery that ion irradiation of microporous water ice exposed to gaseous oxygen enhances adsorption and retention of O2. We investigated how the irradiation history of ice with and without ambient O2 influences the O2 adsorption on ice. Irradiation by 100 KeV Ar+ or 50 KeV H+ ions in vacuum was found to compact the ice, in agreement with Raut et al. [(2007), J. Chem. Phys., 126, 244511]. This was revealed in a subsequent oxygen exposure which resulted in no O2 adsorption. When ice was irradiated at an ambient O2 pressure of 5.5x10-7 torr, O2 adsorption was enhanced by a factor as high as 5.5 compared to unirradiated ice. The enhanced amount of adsorbed O2 increased with decreasing ion flux. A uniform oxygen concentration of 3% was achieved throughout the ion penetration depth for a low flux limit. After simultaneous irradiation and oxygen exposure, the adsorbed O2 could be retained in the ice when the ambient O2 pressure was removed. The experimental results show that the ion induced enhancement of adsorption and retention of oxygen may explain the difference in the amount of condensed oxygen on the leading vs. trailing sides of Ganymede and Europa [Spencer et. al. (1995), J. Geophys. Res., 100, 19049]. The results also indicate that re-adsorption of atmospheric O2 can not be neglected in exosphere models, since significant amounts of adsorbed O2 could occur in regions with surfaces colder than 50 K or those areas under low flux ion bombardment.
Baragiola Raúl A.
Shi Jianming
Teolis B. D.
No associations
LandOfFree
Irradiation Enhanced Adsorption and Trapping of O2 on Microporous Water Ice does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Irradiation Enhanced Adsorption and Trapping of O2 on Microporous Water Ice, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Irradiation Enhanced Adsorption and Trapping of O2 on Microporous Water Ice will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1066459