Experimental and simulated vibrational spectra of H2 absorbed in amorphous ice: Surface structures, energetics, and relaxations

1992 ◽  
Vol 97 (2) ◽  
pp. 753-767 ◽  
Author(s):  
Holly G. Hixson ◽  
Marek J. Wojcik ◽  
Matthew S. Devlin ◽  
J. Paul Devlin ◽  
V. Buch
Keyword(s):  
Vibrational Spectra ◽  
Surface Structures ◽  
Amorphous Ice ◽  
Ice Surface

scholarly journals Are longitudinal ice-surface structures on the Antarctic Ice Sheet indicators of long-term ice-flow configuration?

2014 ◽  
Vol 2 (2) ◽  
pp. 911-933 ◽  
Author(s):  
N. F. Glasser ◽  
S. J. A. Jennings ◽  
M. J. Hambrey ◽  
B. Hubbard
Keyword(s):  
Flow Line ◽  
Ice Sheet ◽  
Surface Structures ◽  
Surface Velocity ◽  
Ice Flow ◽  
Antarctic Ice Sheet ◽  
Ice Surface ◽  
Ice Stream ◽  
The Antarctic

Abstract. Continent-wide mapping of longitudinal ice-surface structures on the Antarctic Ice Sheet reveals that they originate in the interior of the ice sheet and are arranged in arborescent networks fed by multiple tributaries. Longitudinal ice-surface structures can be traced continuously down-ice for distances of up to 1200 km. They are co-located with fast-flowing glaciers and ice streams that are dominated by basal sliding rates above tens of m yr-1 and are strongly guided by subglacial topography. Longitudinal ice-surface structures dominate regions of converging flow, where ice flow is subject to non-coaxial strain and simple shear. Associating these structures with the AIS' surface velocity field reveals (i) ice residence times of ~ 2500 to 18 500 years, and (ii) undeformed flow-line sets for all major flow units analysed except the Kamb Ice Stream and the Institute and Möller Ice Stream areas. Although it is unclear how long it takes for these features to form and decay, we infer that the major ice-flow and ice-velocity configuration of the ice sheet may have remained largely unchanged for several thousand years, and possibly even since the end of the last glacial cycle. This conclusion has implications for our understanding of the long-term landscape evolution of Antarctica, including large-scale patterns of glacial erosion and deposition.

Similarity of Vibrational Spectra of High Density Amorphous Ice and High Pressure Phase Ice Vi

1994 ◽  
Vol 376 ◽  
Author(s):  
A.I. KOLESNIKOV
Keyword(s):  
High Pressure ◽  
Hydrogen Bonds ◽  
Neutron Scattering ◽  
Amorphous Phase ◽  
Vibrational Spectra ◽  
Amorphous Ice ◽  
Incoherent Neutron Scattering ◽  
Scattering Measurements ◽  
Pressure Phase ◽  
Incoherent Neutron

ABSTRACTInelastic incoherent neutron scattering measurements on the hdaice, ice Ih and high-pressure phases ice VI and ice VIII revealed similarity between the amorphous phase and crystalline ice VI and led to the new proposition that hda ice consists of two interpenetrating hydrogen-bonded networks with no hydrogen bonds between “sublattices”.

Experimental and Theoretical Investigation of HC5N Adsorption on Amorphous Ice Surface: Simulation of the Interstellar Chemistry

2008 ◽  
Vol 112 (35) ◽  
pp. 8024-8029 ◽  
Author(s):  
Anne Coupeaud ◽  
Nathalie Piétri ◽  
Alain Allouche ◽  
Jean-Pierre Aycard ◽  
Isabelle Couturier-Tamburelli
Keyword(s):  
Theoretical Investigation ◽  
Interstellar Chemistry ◽  
Amorphous Ice ◽  
Ice Surface

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.

Measurement of the Adsorption Energy Difference betweenOrtho- andPara-D2on an Amorphous Ice Surface

2008 ◽  
Vol 100 (5) ◽  
Author(s):  
L. Amiaud ◽  
A. Momeni ◽  
F. Dulieu ◽  
J. H. Fillion ◽  
E. Matar ◽  
...  
Keyword(s):  
Adsorption Energy ◽  
Energy Difference ◽  
Amorphous Ice ◽  
Ice Surface

Identifying and mapping very small mountain glaciers on coarse to high-resolution imagery

2020 ◽  
Author(s):  
Joshua Leigh ◽  
Chris Stokes ◽  
Rachel Carr ◽  
Ian Evans ◽  
Liss Andreassen ◽  
...  
Keyword(s):  
High Resolution ◽  
Surface Structures ◽  
Minimum Size ◽  
Minimum Threshold ◽  
Mountain Glaciers ◽  
Seasonal Snow ◽  
Ice Surface ◽  
High Resolution Imagery ◽  
Glacial Landforms ◽  
Seasonal Snow Cover

<p>Small mountain glaciers are an important part of the cryosphere and tend to respond rapidly to climate warming. Historically, mapping very small glaciers (generally considered to be <0.5 km<sup>2</sup>) using satellite imagery has often been subjective due to the difficulty in differentiating them from perennial snowpatches. For this reason, most scientists implement minimum size-thresholds (typically 0.01–0.05 km<sup>2</sup>). However, when mapping on high-resolution imagery (<1 m) with minimal seasonal snow cover, glaciers <0.05 km<sup>2 </sup>and even <0.01 km<sup>2 </sup>are readily identifiable and using a minimum threshold may be inappropriate. For these cases, we have developed a set of criteria to enable the identification of very small glaciers and classify them as <em>certain</em>, <em>probable</em>, or <em>possible</em>. Our identification criteria are based on detailed ice surface structures (e.g. evidence of flow banding and crevasses) and diagnostic glacial landforms (e.g. moraines). Implementation of this scoring system should facilitate a more consistent and objective approach to identifying and mapping very small glaciers on high-resolution imagery, helping to produce more comprehensive and accurate glacier inventories.</p>

Similarity of vibrational spectra of high-density amorphous ice and high-pressure phase ice VI

1995 ◽  
Vol 213-214 ◽  
pp. 474-476 ◽  
Author(s):  
A.I. Kolesnikov ◽  
V.V. Sinitsyn ◽  
E.G. Ponyatovsky ◽  
I. Natkaniec ◽  
L.S. Smirnov
Keyword(s):  
High Pressure ◽  
Vibrational Spectra ◽  
High Density ◽  
High Pressure Phase ◽  
Amorphous Ice ◽  
Pressure Phase

Vibrational spectra of high- and low-density amorphous ice, ice Ic, and ice Ih by neutron scattering

1990 ◽  
Vol 4 (1-6) ◽  
pp. 528-530 ◽  
Author(s):  
D. D. Klug ◽  
Edward Whalley ◽  
E. C. Svensson ◽  
V. F. Sears ◽  
J. H. Root ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Vibrational Spectra ◽  
Low Density ◽  
Amorphous Ice

scholarly journals Origin and dynamic significance of longitudinal structures ("flow stripes") in the Antarctic Ice Sheet

2015 ◽  
Vol 3 (2) ◽  
pp. 239-249 ◽  
Author(s):  
N. F. Glasser ◽  
S. J. A. Jennings ◽  
M. J. Hambrey ◽  
B. Hubbard
Keyword(s):  
Large Scale ◽  
Ice Sheet ◽  
Surface Structures ◽  
Dimensional Structure ◽  
Ice Flow ◽  
Antarctic Ice Sheet ◽  
Flow Perturbation ◽  
Ice Surface ◽  
Ice Stream ◽  
The Antarctic

Abstract. Longitudinal ice-surface structures in the Antarctic Ice Sheet can be traced continuously down-ice for distances of up to 1200 km. A map of the distribution of ~ 3600 of these features, compiled from satellite images, shows that they mirror the location of fast-flowing glaciers and ice streams that are dominated by basal sliding rates above tens of metres per annum and are strongly guided by subglacial topography. Longitudinal ice-surface structures dominate regions of converging flow, where ice flow is subject to non-coaxial strain and simple shear. They can be traced continuously through crevasse fields and through blue-ice areas, indicating that they represent the surface manifestation of a three-dimensional structure, interpreted as foliation. Flow lines are linear and undeformed for all major flow units described here in the Antarctic Ice Sheet except for the Kamb Ice Stream and the Institute and Möller Ice Stream areas, where areas of flow perturbation are evident. Parcels of ice along individual flow paths on the Lambert Glacier, Recovery Glacier, Byrd Glacier and Pine Island Glacier may reside in the glacier system for ~ 2500 to 18 500 years. Although it is unclear how long it takes for these features to form and decay, we infer that the major ice-flow configuration of the ice sheet may have remained largely unchanged for the last few hundred years, and possibly even longer. This conclusion has implications for our understanding of the long-term landscape evolution of Antarctica, including large-scale patterns of glacial erosion and deposition.

Adsorbate-induced changes in the structure of amorphous thin films of ice

2003 ◽  
Vol 81 (1-2) ◽  
pp. 167-174 ◽  
Author(s):  
P Swiderek
Keyword(s):  
Film Growth ◽  
Band System ◽  
Vibrational Modes ◽  
Amorphous Thin Films ◽  
Amorphous Ice ◽  
Ice Surface ◽  
Ice Films ◽  
Reflection Absorption Infrared Spectroscopy ◽  
Uppermost Layer ◽  
Induced Changes

The effect of adsorption of thiophene on the infrared spectra of thin amorphous ice films deposited on Pt(111) is studied using reflection-absorption infrared spectroscopy (RAIRS). The changes within the RAIR spectra in the range of the O–H-stretching band system upon adsorption depend on the structure of the ice films and the temperature at which the thiophene is deposited. Preferred binding at the ice surface to sites that are most likely identical with dangling-H groups occurs only if adsorbate mobility is sufficiently high. Otherwise, random film growth is observed, i.e., formation of multilayer islands before the first layer of thiophene on ice is completed. The adsorbate-induced changes within the O–H-stretching band system of the ice films are different for these two situations. Binding to dangling-H sites is shown to influence more than the uppermost layer of the ice, whereas random deposition has an effect only on surface vibrational modes. PACS Nos.: 68.43Fg, 62.35Ja

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