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Liquid water in the domain of cubic crystalline ice IcVapor-deposited amorphous water ice when warmed above the glass transition temperature (120-140 K), is a viscous liquid which exhibits a viscosity vs temperature relationship different from that of liquid water at room temperature. New studies of thin water ice films now demonstrate that viscous liquid water persists in the temperature range 140-210 K. where it coexists with cubic crystalline ice. The liquid character of amorphous water above the glass transition is demonstrated by (1) changes in the morphology of water ice films on a nonwetting surface observed in transmission electron microscopy (TEM) at around 175 K during slow warming, (2) changes in the binding energy of water molecules measured in temperature programmed desorption (TPD) studies, and (3) changes in the shape of the 3.07 micrometers absorption band observed in grazing angle reflection-absorption infrared spectroscopy (RAIRS) during annealing at high temperature. whereby the decreased roughness of the water surface is thought to cause changes in the selection rules for the excitation of O-H stretch vibrations. Because it is present over such a wide range of temperatures, we propose that this form of liquid water is a common material in nature. where it is expected to exist in the subsurface layers of comets and on the surfaces of some planets and satellites.
Document ID
20040089004
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Jenniskens, P.
(The SETI Institute Mountain View, California 94043, United States)
Banham, S. F.
Blake, D. F.
McCoustra, M. R.
Date Acquired
August 21, 2013
Publication Date
July 22, 1997
Publication Information
Publication: The Journal of chemical physics
Volume: 107
Issue: 4
ISSN: 0021-9606
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NCC2-572
Distribution Limits
Public
Copyright
Other
Keywords
NASA Center ARC
NASA Discipline Exobiology

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