Microscopic Mechanism and Kinetics of Ice Formation at Complex Interfaces: Zooming in on Kaolinite
نویسندگان
چکیده
Most ice in nature forms because of impurities which boost the exceedingly low nucleation rate of pure supercooled water. However, the microscopic details of ice nucleation on these substances remain largely unknown. Here, we have unraveled the molecular mechanism and the kinetics of ice formation on kaolinite, a clay mineral playing a key role in climate science. We find that the formation of ice at strong supercooling in the presence of this clay is about 20 orders of magnitude faster than homogeneous freezing. The critical nucleus is substantially smaller than that found for homogeneous nucleation and, in contrast to the predictions of classical nucleation theory (CNT), it has a strong two-dimensional character. Nonetheless, we show that CNT describes correctly the formation of ice at this complex interface. Kaolinite also promotes the exclusive nucleation of hexagonal ice, as opposed to homogeneous freezing where a mixture of cubic and hexagonal polytypes is observed.
منابع مشابه
Ice formation on kaolinite: Insights from molecular dynamics simulations.
The formation of ice affects many aspects of our everyday life as well as important technologies such as cryotherapy and cryopreservation. Foreign substances almost always aid water freezing through heterogeneous ice nucleation, but the molecular details of this process remain largely unknown. In fact, insight into the microscopic mechanism of ice formation on different substrates is difficult ...
متن کاملThe microscopic features of heterogeneous ice nucleation may affect the macroscopic morphology of atmospheric ice crystals.
It is surprisingly difficult to freeze water. Almost all ice that forms under "mild" conditions (temperatures > -40 degrees C) requires the presence of a nucleating agent--a solid particle that facilitates the freezing process--such as clay mineral dust, soot or bacteria. In a computer simulation, the presence of such ice nucleating agents does not necessarily alleviate the difficulties associa...
متن کاملTheoretical study on the mechanism of hydromethoxylation catalyzed by palladium(II) complex
Palladium (II) coordination complexes catalyze the reaction of alcohols with ketones to yield ethers. During the catalytic cycle, the alcohol adds selectively to the β-carbon (anti-Markovnikov). In this work, mechanism and kinetics for the reaction of methanol with methyl vinyl ketone (MVK), being catalyzed by Pd, has been theoretically investigated in detail. Using quantum mechanical approach,...
متن کاملPlatinum-oxygen Bond Formation: Kinetic and Mechanistic Studies
Reaction of [PtMe(C^N)(SMe2)] (C^N = 2-phenylpyridinate (ppy); 1a, C^N = benzo[h]quinolate, (bhq); 1b) with hydrogen peroxide gives the platinum(IV) complexes trans-[PtMe(OH)2(C^N)(H2O)] (C^N = ppy; 3a, C^N = bhq, 3b) bearing platinum-oxygen bonds. The Pt(II) complexes 1a and 1b have 5dπ(Pt)→π*(C^N) MLCT band in the visible region which is used to easily follow the kinetic of its reaction with ...
متن کاملThermodynamics and Kinetics of Spiro-Heterocycle Formation Mechanism: Computational Study
Reaction mechanism among indoline-2,3-dione, pyrrolidine-2-carboxylic acid and (Z)-2-(1-(2-hydroxynaphthalen-1-yl)ethylidene)hydroxycarboxamide to form 1’-((((aminooxy)carbonyl)amino)methyl)-2’-(1-hydroxynaphthalen-2-yl)-2’-methyl-1’,2’,5’,6’,7’,7a’-hexahydrospiro[indoline-3,3’-pyrrolo[1,2-a]imidazole-2-one was investigated using density functional theory (DFT) at B3LYP basis theory. The three-...
متن کامل