On ice surfaces

Figure 5.19 Formation of amino acids on ice surfaces irradiated in the laboratory (Nature Nature 416, 403-406 (28 March 2002) doi 10.1038/416403a-permission granted). Data were obtained from analysis of the room temperature residue of photoprocessed interstellar medium ice analogue taken after 6 M HCl hydrolysis and derivatization (ECEE derivatives, Varian-Chrompack Chirasil-L-Val capillary column 12 m x 0.25 mm inner diameter, layer thickness 0.12 pirn splitless injection, 1.5 ml min-1 constant flow of He carrier gas oven temperature programmed for 3 min at 70°C, 5°C min-1, and 17.5 min at 180°C detection of total ion current with GC-MSD system Agilent 6890/5973). The inset shows the determination of alanine enantiomers in the above sample (Chirasil-L-Val 25 m, single ion monitoring for Ala-ECEE base peak at 116 a.m.u.). DAP, diaminopentanoic acid DAH, diaminohexanoic acid a.m.u., atomic mass units.

Moudrakovski, I.L. Sanchez, A.A. Ratcliffe, C.I. Ripmeester, J.A. (2001). Nucleation and Growth of Hydrates on Ice Surfaces New Insights from 129Xe NMR Experiments with Hyperpolarized Xenon. J. Phys. Chem. B, 105, 12338-12347. 

Similarly, the reaction of HC1 with N205 is slow in the gas phase, but was shown in the late 1980s to occur rapidly on ice surfaces or in the solutions found in stratospheric particles (Tolbert et al., 1988b Leu, 1988b) ... 

Hanson, D. R., and A. R. Ravishankara, Reactions of Halogen Species on Ice Surfaces, in The Tropospheric Chemistiy of Ozone in the Polar Regions (H. Niki and K. H. Becker, Eds.), NATO ASI Series, Vol. 17, Springer-Verlag, Berlin/New York, 1993a. 

Leu, M.-T., Heterogeneous Reactions of N20 with H20 and HCI on Ice Surfaces Implications for Antarctic Ozone Depletion, Geophys. Res. Lett, 15, 853-854 (3988b). 

Tolbert, M. A., M. J. Rossi, and D. M. Golden, Antarctic Ozone Depletion Chemistry Reactions of N205 with H20 and HCI on Ice Surfaces, Science, 240, 1018-1021 (1988b). 

Chu LT, Leu MT, Keyser LF (1993) Heterogeneous reactions of hypochlorous acid + hydrogen chloride - Cl2 + H20 and chlorosyl nitrite + HC1 — Cl2 + HNOs on ice surfaces at polar stratospheric conditions. J Phys Chem 97 12798—12804... 

Comparative SEM investigations show that large frost crystals appear on ice surfaces at relative humidity >10% (Fig.3a and 3b, RH=30%), while the ice surface at a relative humidity of <5% is flat and dense without secondary alteration (Fig.3c and 3d, RH=3%). 

Carbonaceous PM adsorbed on ice surfaces decrease their albedo resulting in more somlight being absorbed by the ice, leading to an increased ice melting rate compared to that found on pure glacial ice. 

It is useful to note that reaction Rl competes with reaction R2 for the available CIONO2 on liquid aerosol surfaces. Thus if HCl has been depleted, the rate of the latter reaction increases, so that effective heterogeneous activation of chlorine is not dependent upon both HCl and CIONO2 being present. Further, the reactions of HCl with HOCl (R3) are also quite efficient on liquid aerosol under moderately cold and/or wet conditions. CIONO2 hydrolysis may proceed via nucleophilic attack at Cl by a lattice water molecule of ice in concert with proton transfer. It is also possible that Cl is formed on ice surfaces, allowing an ion-assisted reaction with C10N02. ... 

The nucleation and growth of hydrates on ice surfaces have been studied using hyperpolarised Xe NMR spectroscopy. Xe NMR spectroscopy has been used to study diffusion in water-saturated porous media. The temperature dependence of the hyper-polarised Xe NMR signal has been used to study the interconversion of species in ice and THF hydrate. ... 

Hidaka H, Watanabe N, Shiraki T, Nagaoka A, Kouchi A (2004) Conversion of H2CO to CH3OH by reactirais of cold atomic hydrogen on ice surfaces below 20 K. Astrophys J 614 1124-1131... 

In the atmosphere, the halogen reservoir compound, ClONOj is converted to CI2 on polar stratospheric cloud surfaces by heterogeneous reactions. This leads to destruction of polar ozone through reactions on ice surfaces such as... 

Q.-B. Lu, Phys. Rep., 487,141-167 (2010). Cosmic-Ray-Driven Electron-Induced Reactions of Halogenated Molecules Adsorbed on Ice Surfaces Implications for Atmospheric Ozone Depletion and Global Climate Change. 

We discuss about the structures of ice surfaces and ice-water interfaces in this chapter. In Section 17.2, the basic thermodynamics of ice surfaces covered with the QLL are described. In Sections 17.3 and 17.4, experimental results for ice surfaces near the melting point and ice-water interfaces are described. In Section 17.5, results of molecular dynamics (MD) simulation studies on ice surfaces and ice-water interfaces are presented. In Section 17.6, protein molecules effects on ice crystal growth in supercooled water are briefly introduced. A short summary is given in Section 17.7. 

Interaction of acidic gases such as HCl with ice particles of PSCs is a key step in polar ozone hole chemistry [3]. The uptake efficiency of HCl, y, on ice is defined by the fractional collision frequency that leads to the reactant loss on ice surface. Until recently, a single laboratory measurement y 0.4 has been performed at HCl vapor... 

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