Nucleation of Ice on Mica

Layton, R. Gary; Harris, Franklin S.

doi:10.1175/1520-0469(1963)020<0142:noiom>2.0.co;2

Cited by 12 publications

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“…This means that at temperatures above −38 • C, the growth of ice on mica is apparently a two-step process: water first condenses and then freezes. This confirms, at the molecular level, the two-stage nucleation hypothesis which suggests that a nucleus forms as a liquid cluster and then freezes (Layton and Harris, 1963;Lupi et al, 2014). Further pumping of the gas mixture to the measuring cell allows the growth of the ice film by diffusion.…”

Section: Resultsmentioning

confidence: 99%

“…An early study, which used a projection microscope and focused on the deposition nucleation of ice on freshly cleaved synthetic fluorophlogopite mica, which is similar in structure to muscovite but has the hydroxyl groups replaced by fluorine, revealed that there is no growth of ice until saturation with respect to water is reached (Layton and Harris, 1963). The authors concluded that at temperatures above −40 • C, the growth of ice on mica should be a two-step process: a nucleus forms as water and then freezes.…”

Section: Introductionmentioning

confidence: 99%

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Direct molecular-level characterization of different heterogeneous freezing modes on mica – Part 1

Abdelmonem

2017

Atmos. Chem. Phys.

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Abstract. The mechanisms behind heterogeneous ice nucleation are of fundamental importance to the prediction of the occurrence and properties of many cloud types, which influence climate and precipitation. Aerosol particles act as cloud condensation and freezing nuclei. The surface-water interaction of an ice nucleation particle plays a major, not well explored, role in its ice nucleation ability. This paper presents a real-time molecular-level comparison of different freezing modes on the surface of an atmospherically relevant mineral surface (mica) under varying supersaturation conditions using second-harmonic generation spectroscopy. Two sub-deposition nucleation modes were identified (one-and two-stage freezing). The nonlinear signal at the water-mica interface was found to drop following the formation of a thin film on the surface regardless of (1) the formed phase (liquid or ice) and (2) the freezing path (one or two step), indicating similar molecular structuring. The results also revealed a transient phase of ice at water-mica interfaces during freezing, which has a lifetime of around 1 min. Such information will have a significant impact on climate change, weather modification, and the tracing of water in hydrosphere studies.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Direct molecular-level characterization of different heterogeneous freezing modes on mica – Part 1

Abdelmonem

2017

Atmos. Chem. Phys.

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“…This dissolution incongruence leads to a layer leached in Al, with a thickness that depends on the specific feldspar and increases with decreasing pH. At steady state, this Al-depleted layer is 6.6-8.5 nm thick for microcline at pH 1 (Lee et al, 2008), but only 1-2 nm at pH 3 (Stillings and Brantley, 1995). For andesine, it reaches 60-120 nm at pH 3.5 and still 15-30 nm at pH 5.7 (Muir et al, 1990).…”

Section: Aluminum Depletion and Surface Dissolutionmentioning

confidence: 99%

“…In pure water, the native charge-balancing surface cations (K + , Na + , Ca 2+ ) immediately undergo cation exchange by H + /H 3 O + (Chardon et al, 2006;Lee et al, 2008), with hardly any simultaneous structural surface damage (Busenberg and Clemency, 1976). The native cation may also participate in ion exchange with an externally added cation depending on the size and charge compatibility of the latter with the crystal structure (Auerbach et al, 2003;Belchinskaya et al, 2013).…”

Section: Surface Ion Exchangementioning

confidence: 99%

Ice nucleation activity of silicates and aluminosilicates in pure water and aqueous solutions – Part 3: Aluminosilicates

2019

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Abstract. Aluminosilicates and quartz constitute the majority of airborne mineral dust. Despite similarities in structures and surfaces they differ greatly in terms of their ice nucleation (IN) efficiency. Here, we show that determining factors for their IN activity include surface ion exchange, NH3 or NH4+ adsorption, and surface degradation due to the slow dissolution of the minerals. We performed immersion freezing experiments with the (Na-Ca)-feldspar andesine, the K-feldspar sanidine, the clay mineral kaolinite, the micas muscovite and biotite, and gibbsite and compare their IN efficiencies with those of the previously characterized K-feldspar microcline and quartz. Samples were suspended in pure water as well as in aqueous solutions of NH3, (NH4)2SO4, NH4Cl and Na2SO4, with solute concentrations corresponding to water activities aw equal to 0.88–1.0. Using differential scanning calorimetry (DSC) on emulsified micron-sized droplets, we derived onset temperatures of heterogeneous (Thet) and homogeneous (Thom) freezing as well as heterogeneously frozen water volume fractions (Fhet). Suspensions in pure water of andesine, sanidine and kaolinite yield Thet equal to 242.8, 241.2 and 240.3 K, respectively, while no discernable heterogeneous freezing signal is present in the case of the micas or gibbsite (i.e., Thet≈Thom≈237.0 K). The presence of NH3 and/or NH4+ salts as solutes has distinct effects on the IN efficiency of most of the investigated minerals. When feldspars and kaolinite are suspended in very dilute solutions of NH3 or NH4+ salts, Thet shifts to higher temperatures (by 2.6–7.0 K compared to the pure water suspension). Even micas and gibbsite develop weak heterogeneous freezing activities in ammonia solutions. Conversely, suspensions containing Na2SO4 cause the Thet of feldspars to clearly fall below the water-activity-based immersion freezing description (Δaw= const.) even in very dilute Na2SO4 solutions, while Thet of kaolinite follows the Δaw= constant curve. The water activity determines how the freezing temperature is affected by solute concentration alone, i.e., if the surface properties of the ice nucleating particles are not affected by the solute. Therefore, the complex behavior of the IN activities can only be explained in terms of solute-surface-specific processes. We suggest that the immediate exchange of the native cations (K+, Na+, Ca2+) with protons, when feldspars are immersed in water, is a prerequisite for their high IN efficiency. On the other hand, excess cations from dissolved alkali salts prevent surface protonation, thus explaining the decreased IN activity in such solutions. In kaolinite, the lack of exchangeable cations in the crystal lattice explains why the IN activity is insensitive to the presence of alkali salts (Δaw= const.). We hypothesize that adsorption of NH3 and NH4+ on the feldspar surface rather than ion exchange is the main reason for the anomalous increased Thet in dilute solutions of NH3 or NH4+ salts. This is supported by the response of kaolinite to NH3 or NH4+, despite lacking exchangeable ions. Finally, the dissolution of feldspars in water or solutions leads to depletion of Al and formation of an amorphous layer enriched in Si. This hampers the IN activity of andesine the most, followed by sanidine, then eventually microcline, the least soluble feldspar.

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“…4.5 Cold stage experiments with freshly cleaved fluor-phlogopite mica by Layton and Harris (1963) Layton and Harris (1963) observed pre-activation on freshly cleaved, synthetic fluor-phlogopite mica mounted on a microscope in a cold chamber with independent temperature and humidity control. Relative humidity was regulated by a temperature controlled ice surface on the bottom of the chamber.…”

Section: Cloud Chamber Experiments By Mason and Maybank (1958)mentioning

confidence: 99%

Pre-activation of aerosol particles by ice preserved in pores

Marcolli

2017

Atmos. Chem. Phys.

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Abstract. Pre-activation denotes the capability of particles or materials to nucleate ice at lower relative humidities or higher temperatures compared to their intrinsic ice nucleation efficiency after having experienced an ice nucleation event or low temperature before. This review presumes that ice preserved in pores is responsible for pre-activation and analyses pre-activation under this presumption. Idealized trajectories of air parcels are used to discuss the pore characteristics needed for ice to persist in pores and to induce macroscopic ice growth out of the pores. The pore width needed to keep pores filled with water decreases with decreasing relative humidity as described by the inverse Kelvin equation. Thus, narrow pores remain filled with ice well below ice saturation. However, the smaller the pore width, the larger the melting and freezing point depressions within the pores. Therefore, pre-activation due to pore ice is constrained by the melting of ice in narrow pores and the sublimation of ice from wide pores imposing restrictions on the temperature and relative humidity range of pre-activation for cylindrical pores. Ice is better protected in ink-bottle-shaped pores with a narrow opening leading to a large cavity. However, whether pre-activation is efficient also depends on the capability of ice to grow macroscopically, i.e. out of the pore. A strong effect of pre-activation is expected for swelling pores, because at low relative humidity (RH) their openings narrow and protect the ice within them against sublimation. At high relative humidities, they open up and the ice can grow to macroscopic size and form an ice crystal. Similarly, ice protected in pockets is perfectly sheltered against sublimation but needs the dissolution of the surrounding matrix to be effective. Pores partially filled with condensable material may also show preactivation. In this case, complete filling occurs at lower RH than for empty pores and freezing shifts to lower temperatures.Pre-activation experiments confirm that materials susceptible to pre-activation are indeed porous. Pre-activation was observed for clay minerals like illite, kaolinite, and montmorillonite with inherent porosity. The largest effect was observed for the swelling clay mineral montmorillonite. Some materials may acquire porosity, depending on the formation and processing conditions. Particles of CaCO 3 , meteoritic material, and volcanic ash showed pre-activation for some samples or in some studies but not in other ones. Quartz and silver iodide were not susceptible to pre-activation.Atmospheric relevance of pre-activation by ice preserved in pores may not be generally given but depend on the atmospheric scenario. Lower-level cloud seeding by pre-activated particles released from high-level clouds crucially depends on the ability of pores to retain ice at the relative humidities and temperatures of the air masses they pass through. Porous particles that are recycled in wave clouds may show pre-activation with subsequent ice growth as soon as ice sat...

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Nucleation of Ice on Mica

Cited by 12 publications

References 0 publications

Direct molecular-level characterization of different heterogeneous freezing modes on mica – Part 1

Direct molecular-level characterization of different heterogeneous freezing modes on mica – Part 1

Ice nucleation activity of silicates and aluminosilicates in pure water and aqueous solutions – Part 3: Aluminosilicates

Pre-activation of aerosol particles by ice preserved in pores

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