Transitions in pressure-amorphized clathrate hydrates akin to those of amorphous ices

2019 ◽  
Vol 151 (1) ◽  
pp. 014502 ◽  
Author(s):  
Ove Andersson ◽  
Paulo H. B. Brant Carvalho ◽  
Ying-Jui Hsu ◽  
Ulrich Häussermann
Keyword(s):  
Clathrate Hydrates ◽  
Amorphous Ices

scholarly journals Physical Properties of Frozen Volatiles–Their Relevance to the Study of Comet Nuclei

1989 ◽  
Vol 116 (1) ◽  
pp. 227-241
Author(s):  
J. Klinger
Keyword(s):  
Physical Properties ◽  
Gas Production ◽  
Clathrate Hydrates ◽  
Cometary Nuclei ◽  
Water Ice ◽  
Kinetics Of Formation ◽  
Amorphous Ices ◽  
Comet Nuclei ◽  
Heating Up ◽  
Kinetics Of

AbstractThe structural and thermodynamical properties of water ice and ice mixtures containing CO, CO2, CH4, and NH3 are thought to be important for the evolution of cometary nuclei. Based on recent laboratory studies performed by several groups, an overview is given of the properties of various ices condensed at low temperatures and of their evolution during heating up to a temperature of about 200 K, typical of the perihelion temperature of a comet such as P/Halley. It is shown that the porous surface of amorphous water ice plays an important role in the retention of other volatiles. The kinetics of formation and of decomposition of clathrate hydrates are discussed. The molecular hydrates formed by NH3 are briefly presented, and the possibility of their occurrence in comet nuclei is discussed. With special attention drawn to amorphous ices and clathrate hydrates, a qualitative discussion of the influence of the physical properties of various types of ices on the thermal behavior of comet nuclei and on gas production rates of comets is presented.

scholarly journals Type II Clathrate Hydrate Formation in Cometary Ice Analogs in Vacuo

1992 ◽  
Vol 150 ◽  
pp. 437-438
Author(s):  
D. F. Blake ◽  
L. Allamandola ◽  
S. Sandford ◽  
D. Hudgins ◽  
F. Freund
Keyword(s):  
High Vacuum ◽  
Hydrate Formation ◽  
Clathrate Hydrate ◽  
Clathrate Hydrates ◽  
Type Ii ◽  
State Transformation ◽  
Solid State Transformation ◽  
Guest Molecules ◽  
Amorphous Ices ◽  
Analog Experiments

Clathrate Hydrates can be formed under high vacuum conditions by annealing vapor-deposited amorphous ices of the appropriate composition. When astrophysically significant H2O:CH3OH ices are deposited and annealed, Type II Clathrate Hydrates are formed which can hold up to 6 mole % large guest molecules such as methanol and 12 mole % small guest molecules such as CO2 and CO. The solid state transformation of amorphous mixed molecular ice into crystalline clathrate hydrate and its sublimation at higher temperatures may serve to explain heretofore anomalous mechanical and gas release properties observed in cometary ices and laboratory ice analog experiments.

Temperature dependence of particle–particle adherence forces in ice and clathrate hydrates

2004 ◽  
Vol 277 (2) ◽  
pp. 335-341 ◽  
Author(s):  
Sung-oh Yang ◽  
Derek M Kleehammer ◽  
Zhongxin Huo ◽  
E.Dendy Sloan ◽  
Kelly T Miller
Keyword(s):  
Temperature Dependence ◽  
Clathrate Hydrates
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