Influence of submonolayer sodium adsorption on the photoemission of the Cu(111)/water ice surface

2006 ◽  
Vol 125 (22) ◽  
pp. 224702 ◽  
Author(s):  
Tomas Vondrak ◽  
John M. C. Plane ◽  
Stephen R. Meech
Keyword(s):  
Water Ice ◽  
Ice Surface

Structural and Phase Transitions on Water Ice Surface Under HCl Exposure: Implication for Stratosphere Conditions

1998 ◽  
Vol 05 (01) ◽  
pp. 437-441
Author(s):  
N. M. Persiantseva ◽  
O. B. Popovicheva ◽  
T. V. Rakhimova
Keyword(s):  
Phase Transitions ◽  
Pressure Range ◽  
Phase State ◽  
Amorphous Solid ◽  
Surface Concentration ◽  
Uptake Kinetics ◽  
Water Ice ◽  
Uptake Efficiency ◽  
Ice Surface ◽  
Characteristic Values

The HCl-ice interaction has been investigated over a wide HCl pressure range of 10-7–10-4 Torr and ice temperatures 150–240 K. The Three characteristic values for HCl uptake efficiency were obtained which indicate the change of phase state and structure of the ice surface at increasing HCl pressure. The low value γ ≈ 0.1 ± 0.02 corresponds to HCl vapor interaction with pure ice and is realized at the atmosphere conditions. The value γ ≈ 0.5 ± 0.1 indicates the formation of hexahydrate HCl • 6H 2 O with increase of HCl pressure. And the largest value of γ ≈ 0.8 ± 0.1 is observed at appearance of liquid or amorphous solid 4:1 H 2O:HCl. The HCl uptake kinetics is analyzed. The flow of HCl molecules from the ice surface into the bulk is shown to play an important role in the redistribution of HCl molecules. It defines a low surface concentration of the adsorbed HCl molecules under stratospher condition at early times of interaction.

scholarly journals The composition of Europa's near-surface atmosphere

2008 ◽  
Vol 4 (S251) ◽  
pp. 327-328
Author(s):  
Mau C. Wong ◽  
Tim Cassidy ◽  
Robert E. Johnson
Keyword(s):  
Solar System ◽  
Surface Composition ◽  
Near Surface ◽  
Water Ice ◽  
Model Studies ◽  
Surface Atmosphere ◽  
Jovian Magnetosphere ◽  
Ice Surface ◽  
Geophysical Phenomenon ◽  
Inorganic Species

AbstractThe presence of an undersurface ocean renders Europa as one of the few planetary bodies in our Solar System that has been conjectured to have possibly harbored life. Some of the organic and inorganic species present in the ocean underneath are expected to transport upwards through the relatively thin ice crust and manifest themselves as impurities of the water ice surface. For this reason, together with its unique dynamic atmosphere and geological features, Europa has attracted strong scientific interests in past decades.Europa is imbedded inside the Jovian magnetosphere, and, therefore, is constantly subjected to the immerse surrounding radiations, similar to the other three Galilean satellites. The magnetosphere-atmosphere-surface interactions form a complex system that provides a multitude of interesting geophysical phenomenon that is unique in the Solar System. The atmosphere of Europa is thought to have created by, mostly, charged particles sputtering of surface materials. Consequently, the study of Europa's atmosphere can be used as a tool to infer the surface composition. In this paper, we will discuss our recent model studies of Europa's near-surface atmosphere. In particular, the abundances and distributions of the dominant O2 and H2O species, and of other organic and inorganic minor species will be addressed.

scholarly journals Investigation of acoustic fields in the arctic zone with uneven ice cover

2021 ◽  
Vol 254 ◽  
pp. 02007
Author(s):  
Vladimir Korochentsev ◽  
Сhen Wenjian ◽  
Victor Petrosyants ◽  
Tatiana Lobova ◽  
Julia Shpak
Keyword(s):  
Wave Propagation ◽  
Acoustic Waves ◽  
Signal Propagation ◽  
Ice Cover ◽  
Measuring System ◽  
The Arctic ◽  
Water Medium ◽  
Water Ice ◽  
Ice Surface ◽  
Hydraulic Generator

A mathematical model for elastic wave propagation in an ice cover with uneven relief (hummock) has been developed. The theoretical model is based on the application of “directed” Green’s functions. We obtained numerical results for different distances between radiating and receiving antennas installed inside the ice layer and in water medium. An information-measuring system was created to investigate elastic acoustic waves along ice surface based on electo-hydraulic generator. Experiments of high-frequency acoustic signal propagation from electro-hydraulic generator in water-ice-air system were carried out. We illustrated the model validity for the investigation of hydroacoustic wave propagation in real ice conditions.

Isotopic segregation of molecular hydrogen on water ice surface at low temperature

2005 ◽  
Vol 404 (1-3) ◽  
pp. 187-191 ◽  
Author(s):  
F. Dulieu ◽  
L. Amiaud ◽  
S. Baouche ◽  
A. Momeni ◽  
J.-H. Fillion ◽  
...  
Keyword(s):  
Low Temperature ◽  
Molecular Hydrogen ◽  
Water Ice ◽  
Ice Surface

scholarly journals Thermal desorption of formamide and methylamine from graphite and amorphous water ice surfaces

2019 ◽  
Vol 15 (S350) ◽  
pp. 370-371
Author(s):  
Henda Chaabouni ◽  
Stephan Diana ◽  
Thanh Nguyen
Keyword(s):  
Energy Distribution ◽  
Thermal Desorption ◽  
Interstellar Dust ◽  
Binding Energies ◽  
Desorption Energy ◽  
Exponential Factor ◽  
Water Ice ◽  
Ice Surface ◽  
Crystalline Water ◽  
Best Fit

AbstractThermal desorption experiments of Formamide (NH2CHO) and methylamine (CH3NH2) were performed in LERMA-Cergy laboratory to determine the values of the desorption energies of formamide and methylamine from analogues of interstellar dust grain surfaces, and to understand their interaction with water ice. We found that more than 95 % of solid NH2CHO diffuses through the np-ASW ice surface towards the graphitic substrate, and is released into the gas phase with a desorption energy distribution Edes = (7460 – 9380) K, measured with the best-fit pre-exponential factor A=1018 s-1. Whereas, the desorption energy distribution of methylamine from the np-ASW ice surface (Edes =3850-8420 K) is measured with the best-fit pre-exponential factor A=1012s-1. A fraction of solid methylamine, of about 0.15 monolayer diffuses through the water ice surface towards the HOPG substrate, and desorbs later, with higher binding energies (5050-8420 K), which exceed that of the crystalline water ice (Edes =4930 K), calculated with the same pre-exponential factor A=1012 s-1.

scholarly journals Modeling climate diversity, tidal dynamics and the fate of volatiles on TRAPPIST-1 planets

2018 ◽  
Vol 612 ◽  
pp. A86 ◽  
Author(s):  
Martin Turbet ◽  
Emeline Bolmont ◽  
Jeremy Leconte ◽  
François Forget ◽  
Franck Selsis ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Planetary Science ◽  
Water Ice ◽  
Planetary Evolution ◽  
Ice Surface ◽  
Surface Condensation ◽  
Synchronous Rotation ◽  
Ice Shell

TRAPPIST-1 planets are invaluable for the study of comparative planetary science outside our solar system and possibly habitability. Both transit timing variations (TTV) of the planets and the compact, resonant architecture of the system suggest that TRAPPIST-1 planets could be endowed with various volatiles today. First, we derived from N-body simulations possible planetary evolution scenarios, and show that all the planets are likely in synchronous rotation. We then used a versatile 3D global climate model (GCM) to explore the possible climates of cool planets around cool stars, with a focus on the TRAPPIST-1 system. We investigated the conditions required for cool planets to prevent possible volatile species to be lost permanently by surface condensation, irreversible burying or photochemical destruction. We also explored the resilience of the same volatiles (when in condensed phase) to a runaway greenhouse process. We find that background atmospheres made of N2, CO, or O2are rather resistant to atmospheric collapse. However, even if TRAPPIST-1 planets were able to sustain a thick background atmosphere by surviving early X/EUV radiation and stellar wind atmospheric erosion, it is difficult for them to accumulate significant greenhouse gases like CO2, CH4, or NH3. CO2can easily condense on the permanent nightside, forming CO2ice glaciers that would flow toward the substellar region. A complete CO2ice surface cover is theoretically possible on TRAPPIST-1g and h only, but CO2ices should be gravitationally unstable and get buried beneath the water ice shell in geologically short timescales. Given TRAPPIST-1 planets large EUV irradiation (at least ~103 × Titan’s flux), CH4and NH3are photodissociated rapidly and are thus hard to accumulate in the atmosphere. Photochemical hazes could then sedimentate and form a surface layer of tholins that would progressively thicken over the age of the TRAPPIST-1 system. Regarding habitability, we confirm that few bars of CO2would suffice to warm the surface of TRAPPIST-1f and g above the melting point of water. We also show that TRAPPIST-1e is a remarkable candidate for surface habitability. If the planet is today synchronous and abundant in water, then it should very likely sustain surface liquid water at least in the substellar region, whatever the atmosphere considered.

Structure of the water ice surface studied by x-ray absorption spectroscopy at the O K-edge

2002 ◽  
Vol 117 (23) ◽  
pp. 10842-10851 ◽  
Author(s):  
Ph. Parent ◽  
C. Laffon ◽  
C. Mangeney ◽  
F. Bournel ◽  
M. Tronc
Keyword(s):  
Absorption Spectroscopy ◽  
X Ray ◽  
Water Ice ◽  
Ice Surface ◽  
X Ray Absorption

The vibrational signatures of polyaromatic hydrocarbons on an ice surface

2019 ◽  
Vol 15 (S350) ◽  
pp. 468-470
Author(s):  
Victoria H.J. Clark ◽  
David M. Benoit
Keyword(s):  
Vibrational Spectra ◽  
Density Functional ◽  
Polyaromatic Hydrocarbons ◽  
Functional Theory ◽  
Water Ice ◽  
Aromatic Molecules ◽  
Ice Surface ◽  
Vibrational Anharmonicity ◽  
Potential Energy Landscape ◽  
Crystalline Water

AbstractWe use quantum chemical techniques to model the vibrational spectra of small aromatic molecules on a proton-ordered hexagonal crystalline water ice (XIh) model. We achieve a good agreement with experimental data by accounting for vibrational anharmonicity and correcting the potential energy landscape for known failures of density functional theory. A standard harmonic description of the vibrational spectra only leads to a broad qualitative agreement.

New Light on the Mode of Uplift of the Fish and Fossiliferous Moraines of the Mcmurdo Ice Shelf, Antarctica

1965 ◽  
Vol 5 (42) ◽  
pp. 813-828 ◽  
Author(s):  
A. J. Gow ◽  
W. F. Weeks ◽  
G. Hendrickson ◽  
R. Rowland
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Marine Invertebrate ◽  
Lower Surface ◽  
Faunal Remains ◽  
Ice Shelf ◽  
Water Ice ◽  
Deep Diving ◽  
Ice Surface ◽  
Fish Remains

Abstract The McMurdo Ice Shelf and associated faunal remains were examined in the vicinity of the easternmost Dailey Island. Stratigraphic, petrographic, and chemical composition studies of cores from two holes drilled through the ice shelf show that at these locations the shelf is composed only of fresh-water ice. Although cores from the deeper hole possessed typically glacial textures throughout, much of the ice from this part of the McMurdo Ice Shelf may have been formed from the freezing of a layer of fresh water found sandwiched between shelf bottom and the underlying sea-water. The existence of fresh water under the ice shelf can most probably be attributed to drainage of surface melt water during the ablation season. There was no evidence to indicate that this part of the McMurdo Ice Shelf is being nourished by the growth of sea ice onto its lower surface. The fish remains found on the ice surface were confined to a narrow zone along the tide crack and are believed to have been left in this vicinity by deep diving seals. The marine invertebrate remains on top of the ice are associated with morainal material and are believed to have been incorporated into the ice at the time of formation of the moraines.

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