The formation of cubic ice under conditions relevant to Earth's atmosphere

@article{Murray2005TheFO,
  title={The formation of cubic ice under conditions relevant to Earth's atmosphere},
  author={Benjamin J. Murray and Daniel A. Knopf and Allan K. Bertram},
  journal={Nature},
  year={2005},
  volume={434},
  pages={202-205}
}
An important mechanism for ice cloud formation in the Earth's atmosphere is homogeneous nucleation of ice in aqueous droplets, and this process is generally assumed to produce hexagonal ice. However, there are some reports that the metastable crystalline phase of ice, cubic ice, may form in the Earth's atmosphere. Here we present laboratory experiments demonstrating that cubic ice forms when micrometre-sized droplets of pure water and aqueous solutions freeze homogeneously at cooling rates… Expand

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References

SHOWING 1-10 OF 41 REFERENCES
Cubic ice from liquid water
Hexagonal ice (ice Ih) is the only form of ice that is known to occur naturally on the Earth. Recently it has been suggested that small droplets of water in the upper atmosphere may often freezeExpand
Dehydration in cold clouds is enhanced by a transition from cubic to hexagonal ice
[1] Cubic ice (Ic) is a metastable form of ice with very similar physical properties but different crystal symmetry than normal, hexagonal ice (Ih). Below 200 K, water preferentially nucleates to Ic,Expand
On the role of cubic structure in ice nucleation
Abstract To clarify the formation mechanism of snow polycrystals the possibility of formation of a cubic ice embryo is discussed on the basis of the homogeneous nucleation theory for supercooledExpand
Ice Formation in (NH4)2SO4−H2O Particles
Ice nucleation in upper tropospheric aerosols is believed to be a key step in upper tropospheric cloud formation, and therefore knowledge of the conditions leading to ice formation in these aerosolsExpand
Scheiner's Halo: Evidence for Ice Ic in the Atmosphere.
TLDR
It is suggested that Scheiner's halo, which has been reported at least four times since 1629 at 28 degrees from the sun, is due to ice Ic, apparently the first evidence that ice Ic occurs naturally and that liquid water can freeze toIce Ic. Expand
Structural transitions in amorphous water ice and astrophysical implications.
TLDR
The structural transition from Iah to Ial is responsible for the diffusion and recombination of radicals in ultraviolet-photolyzed interstellar ices at low temperatures and can be used to explain hitherto anomalous properties of astrophysical ices. Expand
The uptake of atomic oxygen on ice films: Implications for noctilucent clouds
Rocket-borne measurements show that atomic oxygen is often depleted by more than an order of magnitude in the vicinity of noctilucent clouds (NLCs). These are clouds that occur in the upperExpand
Microphysics and heterogeneous chemistry of polar stratospheric clouds.
  • T. Peter
  • Chemistry, Medicine
  • Annual review of physical chemistry
  • 1997
TLDR
There are indications that the rates of key heterogeneous reactions have not yet been established with sufficient accuracy to enable a reliable diagnosis of observed ozone losses by means of global models. Expand
Evidence That Nitric Acid Increases Relative Humidity in Low-Temperature Cirrus Clouds
TLDR
It is proposed that surface HNO3 molecules prevent the ice/vapor system from reaching equilibrium by a mechanism similar to that of freezing point depression by antifreeze proteins. Expand
Phase transitions of sea-salt/water mixtures at low temperatures: Implications for ozone chemistry in the polar marine boundary layer
We present laboratory experiments employing differential scanning calorimetry as well as flow cell microscopy to study the microphysics of aqueous NaCl and sea-salt solutions and droplets atExpand
...
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3
4
5
...