A5028376373- Crystallization and Solubility Studies
- nanoparticles nucleation surface interactions
- Calcium Carbonate Crystallization and Inhibition
- Theoretical and Computational Physics
- X-ray Diffraction in Crystallography
- Material Dynamics and Properties
- Graphene research and applications
- Coal and Its By-products
- Metal Extraction and Bioleaching
- Chemical Safety and Risk Management
- Spectroscopy and Quantum Chemical Studies
- Carbon Nanotubes in Composites
- Minerals Flotation and Separation Techniques
- Polysaccharides and Plant Cell Walls
- Crystallography and molecular interactions
- Protein Structure and Dynamics
- Enzyme Production and Characterization
- Risk and Safety Analysis
- Enzyme Catalysis and Immobilization
- Biofuel production and bioconversion
- Enzyme Structure and Function
- Quantum, superfluid, helium dynamics
- Machine Learning in Materials Science
- Occupational Health and Safety Research
- Nanowire Synthesis and Applications
University of Warwick
2015-2025
Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine
2017
University of Cambridge
2017
Bristol Robotics Laboratory
2017
University of Ulster
2017
Royal Victoria Hospital
2017
Coventry (United Kingdom)
2015-2017
Daresbury Laboratory
2017
University of Lincoln
2016
Boston College
2014
Calcium carbonate is an abundant substance that can be created in several mineral forms by the reaction of dissolved carbon dioxide water with calcium ions. Through biomineralization, organisms harness and control this process to form various functional materials act as anything from shells through lenses. The early stages formation have recently attracted attention stable prenucleation clusters been observed, contrary classical models. Here we show, using computer simulations combined...
The performance of existing force-field models for the calcium carbonate - water system has been critically assessed with particular reference to thermodynamic consequences. It is demonstrated that all currently available parametrizations fail describe calcite-aragonite phase transition, and free energies solvation cation are also considerably in error leading a poor description dissolution enthalpy calcite. A new force-field, based on rigid ions, developed corrects these deficiencies...
Nucleation of gas hydrates remains a poorly understood phenomenon, despite its importance as critical step in understanding the performance and mode action low dosage hydrate inhibitors. We present here detailed analysis structural mechanistic processes by which nucleate molecular dynamics simulation dissolved methane at methane/water interface. It was found that initially nucleates into phase consistent with none common bulk crystal structures, but containing units all them. The process...
Nucleation and crystal growth are important in material synthesis, climate modeling, biomineralization, pharmaceutical formulation. Despite tremendous efforts, the mechanisms kinetics of nucleation remain elusive to both theory experiment. Here we investigate sodium chloride (NaCl) from supersaturated brines using seeded atomistic simulations, polymorph-specific order parameters, elements classical theory. We find that NaCl nucleates via common rock salt structure. Ion desolvation-not...
The metadynamics method for accelerating rate events in molecular simulations is applied to the problem of ice freezing. We demonstrate homogeneous nucleation and growth at 180 K isothermal-isobaric ensemble without presence external fields or surfaces. This result represents first report continuous dynamic a system freely evolving density. Simulations are conducted using variety periodic simulation domains. In all cases cubic polymorph I(c) grown. influence boundary effects on estimates...
The advantages of performing Langevin dynamics in extended systems are discussed. A simple scheme for producing the canonical ensemble is reviewed, and then to Hoover ensemble. We show that resulting equations motion generate isobaric-isothermal Parrinello-Rahman discussed we despite presence intrinsic probability gradients this system, a approach samples phase space correct fashion. implementation these methods ab initio plane wave density functional theory code CASTEP [M. D. Segall, P. L....
Growing a good egg: Metadynamics simulations show that the eggshell protein ovocleidin-17 induces formation of calcite crystals from amorphous calcium carbonate nanoparticles. Multiple spontaneous crystallization and amorphization events were simulated; these suggest catalytic cycle explains role in first stages (the picture shows one intermediate this cycle). Detailed facts importance to specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not...
Extreme nanowires (ENs) represent the ultimate class of crystals: They are smallest possible periodic materials. With atom-wide motifs repeated in one dimension (1D), they offer a privileged perspective into Physics and Chemistry low-dimensional systems. Single-walled carbon nanotubes (SWCNTs) provide ideal environments for creation such Here we present comprehensive study Te ENs encapsulated inside ultra- narrow SWCNTs with diameters between 0.7 nm 1.1 nm. We combine state-of-the-art...
This work reexamines seeded simulation results for NaCl nucleation from a supersaturated aqueous solution at 298.15 K and 1 bar pressure. We present linear regression approach analyzing data that provides both rates uncertainty estimates. Our show obtained simulations rely critically on precise driving force the model system. The vs. solute concentration curve need not exactly reproduce of real system, but it should accurately describe thermodynamic properties also rate estimates depend...
The formation of crystals has proven to be one the most challenging phase transformations quantitatively model - let alone actually understand it by means latest experimental technique or full arsenal enhanced sampling approaches at our disposal. One crucial quantities involved with crystallization process is nucleation rate, a single, elusive number that supposed quantify average probability for nucleus critical size occur within certain volume and time span. A substantial amount effort...
We tested the hypotheses that (1) an incomplete oxidation of carbon-based fossil fuels during their combustion produces humic-like substances (HIS), which can be present in air pollution particulates and confer a capacity to complex metals; (2) collected on PM10 filters associated with concentrations first-row transition (3) catalyze production free radicals by cycling these metals through two stable valence states; (4) oxidant generation increase content HLS particles. were isolated alkali...
We introduce a metadynamics based scheme for computing the free energy of nanoparticles as function their crystalline order. The method is applied to small biomineral calcium carbonate determine preferred structure during early stages crystal growth. For particles 2 nm in diameter, we establish large energetic preference amorphous particle morphologies. Particles with partial order consistent vaterite are also observed substantially lower probability. absence stable calcite phase and...
Ovocleidin-17 has been identified as a major eggshell-forming protein although the role and function it performs is still uncertain. Classical molecular dynamics simulations are presented for adsorption of whole ovocleidin-17 onto {10.4} surface calcite in several different configurations. For each configuration detailed data bound with hydrogen-bond analysis, structural examination, energies. The demonstrate that binding competition between strongly water such most energetically favorable...
Organic additives are well known to influence the nucleation and growth of minerals. A combination experimental theoretical methods has been used probe how three simple additives, containing varying numbers carboxylate groups, early stages calcium carbonate. Computationally, free energy landscape examined for each additive binding Ca2+, carbonate ion pair, surface an amorphous nanoparticle, basal plane calcite. The different organic ligands on observed experimentally can be rationalised in...
Nanostructuring, e.g., reduction of dimensionality in materials, offers a viable route toward regulation materials electronic and hence functional properties. Here, we present the extreme case nanostructuring, exploiting capillarity single-walled carbon nanotubes (SWCNTs) for synthesis smallest possible SnTe nanowires with cross sections as thin single atom column. We demonstrate that by choosing appropriate diameter template SWCNT, can manipulate structure quasi-one-dimensional (1D) to...
Covalent functionalization of graphene offers opportunities for tailoring its properties and is an unavoidable consequence some synthesis techniques. However, the changes induced by are not well understood. By using atomic sources to control extent oxygen nitrogen functionalization, we studied evolution in structure at scale. Atomic reversibly introduces epoxide groups whilst, under similar conditions, irreversibly creates diverse functionalities including substitutional, pyridinic, pyrrolic...
One-dimensional (1D) atomic chains of CsI were previously reported in double-walled carbon nanotubes with ∼0.8 nm inner diameter. Here, we demonstrate that, while 1D form within narrow ∼0.73 diameter single-walled (SWCNTs), wider SWCNT tubules (∼0.8-1.1 nm) promote the formation helical 2 × 1 atoms cross-section. These helices create complementary oval distortions encapsulating SWCNTs highly strained formed from Cs2I2 parallelogram units tubes to lower strain tubes. The observed structural...
We discuss the practicalities of applying metadynamics method to sampling crystallisation events in molecular systems. Suitable choices for collective coordinates are presented along with criteria their parameterisation. Issues arising from finite-size effects discussed particular reference generation multiple clusters when biasing global order parameters. also consider applicability two methods enhancing accuracy reconstructed free-energy landscape. The discussion is illustrated example...
Metadynamics is employed to sample the configurations available calcium carbonate nanoparticles in water, and map an approximate free energy as a function of crystalline order. These data are used investigate validity bulk ideal surface energies predicting structure at nanoscale. Results indicate that such predictions can determine morphology particles small 3–4 nm diameter. Comparisons made earlier results on 2 under constant volume conditions which support nanoconfinement mechanism for...
AbstractWe highlight some links between molecular dynamics and Monte Carlo algorithms used to simulate condensed matter systems. Special attention is paid the question of sampling desired statistical ensemble.Keywords: molecular-dynamicsMonte AcknowledgementsWe are happy acknowledge our debt Giovanni Ciccotti, who has long pioneered methods as a viable alternative in variety circumstances. Indeed, one us (MPA) particularly indebted inspiration provided by at CECAM workshop Orsay, 1978, which...
A simple Ising-like model for the stacking thermodynamics of ice 1 is constructed nuclei in supercooled water, and combined with classical nucleation theory. For relative stabilities cubic hexagonal I within range experimental estimates, this predicts critical are disordered at strong sub-cooling, consistent recent experiments. At higher temperatures pure recovered. Lattice-switching Monte-Carlo applied to accurately compute stability popular mW water. Results demonstrate that fails...