Crystallisation in the Real World: Delivering Control through Theory and Experiment
Lead Research Organisation:
University of Leeds
Department Name: Sch of Chemistry
Abstract
Crystallisation is a fascinating process. From common observations such as the formation of ice on a window or scale in a kettle, crystallisation is important to virtually every area of science, and lies at the heart of processes as varied as the production of ceramics, pharmaceuticals, fine chemicals, nanomaterials and biominerals. Equally important is the prevention of unwanted crystallisation in the form of weathering, scale or kidney stones. Only by understanding how materials crystallise can we hope to control these processes.
Despite the importance of crystallisation, we still have a poor understanding of many of the mechanisms that underlie this fundamental phenomenon. This is due to the fact that crystallisation is governed by molecular scale processes that are very difficult to study experimentally. For example, while experiments can identify reaction conditions that generate specific crystal polymorphs, they cannot alone explain why this occurred.
This Programme Grant will couple experiment and theory to address this challenge. Our experimental programme brings to the fore such frontier analytical techniques as liquid-phase TEM and functional scanning probe microscopies that will allow us to study the changes in solid and solution during crystallisation as never before. With recent advances in modelling we shall be able to perform simulations of nucleation and growth processes on comparable time- and length-scales, providing a unique opportunity to fully understand crystal nucleation and growth at the nanoscale. These studies will be linked to simpler bulk experiments to provide a holistic view of crystallisation in the real world.
We will use this approach to address six major challenges in the crystallisation of inorganic compounds. Each challenge, as well as being of fundamental importance, is ultimately significant to industry and has practical applications as varied as scale prevention in dishwashers, dental remineralisation and tailoring particle shape for paper coatings. Investigations of homogeneous crystallisation in bulk solution will lay the foundation for our nucleation studies, revealing how we can direct nucleation pathways by varying solution and environmental conditions. We will then build on this work to explore the fascinating question of polymorphism, giving us predictive understanding of conditions which deliver specific crystal polymorphs. Turning then to the ubiquitous phenomenon of surface-directed crystallisation, both theory and cutting-edge analytical methods will bring new understanding of how surfaces - and the changes they cause in the adjacent solution - govern crystallisation. This naturally leads us to a search for effective nucleating agents, which, despite the promises of classical nucleation theory, are known for only a small number of systems. Control of crystal growth to generate particles with defined shapes and sizes is another topic of great industrial importance, and soluble additives are widely used to achieve this goal. By understanding crystal/ additive interactions we aim to pre-select additives to grow crystals with target properties, or to inhibit unwanted crystallisation. Finally, we will study crystallisation within confined volumes; this will ultimately enable us to use confinement to control crystallisation.
These ambitious objectives can only be met within the framework of a Programme Grant, which provides the flexibility and long-term funding to bring together the very different disciplines of theory and experiment. While each of the individual tasks focuses on a distinct problem in crystallisation, they are intimately linked over the entire project by common methods and understanding, and developments in one task will drive advances in others.
Despite the importance of crystallisation, we still have a poor understanding of many of the mechanisms that underlie this fundamental phenomenon. This is due to the fact that crystallisation is governed by molecular scale processes that are very difficult to study experimentally. For example, while experiments can identify reaction conditions that generate specific crystal polymorphs, they cannot alone explain why this occurred.
This Programme Grant will couple experiment and theory to address this challenge. Our experimental programme brings to the fore such frontier analytical techniques as liquid-phase TEM and functional scanning probe microscopies that will allow us to study the changes in solid and solution during crystallisation as never before. With recent advances in modelling we shall be able to perform simulations of nucleation and growth processes on comparable time- and length-scales, providing a unique opportunity to fully understand crystal nucleation and growth at the nanoscale. These studies will be linked to simpler bulk experiments to provide a holistic view of crystallisation in the real world.
We will use this approach to address six major challenges in the crystallisation of inorganic compounds. Each challenge, as well as being of fundamental importance, is ultimately significant to industry and has practical applications as varied as scale prevention in dishwashers, dental remineralisation and tailoring particle shape for paper coatings. Investigations of homogeneous crystallisation in bulk solution will lay the foundation for our nucleation studies, revealing how we can direct nucleation pathways by varying solution and environmental conditions. We will then build on this work to explore the fascinating question of polymorphism, giving us predictive understanding of conditions which deliver specific crystal polymorphs. Turning then to the ubiquitous phenomenon of surface-directed crystallisation, both theory and cutting-edge analytical methods will bring new understanding of how surfaces - and the changes they cause in the adjacent solution - govern crystallisation. This naturally leads us to a search for effective nucleating agents, which, despite the promises of classical nucleation theory, are known for only a small number of systems. Control of crystal growth to generate particles with defined shapes and sizes is another topic of great industrial importance, and soluble additives are widely used to achieve this goal. By understanding crystal/ additive interactions we aim to pre-select additives to grow crystals with target properties, or to inhibit unwanted crystallisation. Finally, we will study crystallisation within confined volumes; this will ultimately enable us to use confinement to control crystallisation.
These ambitious objectives can only be met within the framework of a Programme Grant, which provides the flexibility and long-term funding to bring together the very different disciplines of theory and experiment. While each of the individual tasks focuses on a distinct problem in crystallisation, they are intimately linked over the entire project by common methods and understanding, and developments in one task will drive advances in others.
Planned Impact
This project will deliver major new capability in understanding and controlling inorganic crystallisation under conditions relevant to real world applications. This will be achieved through a combined experimental and theory approach, led by innovations in experimental methods and theory. The impact will therefore be extremely broad, encompassing all who research, manufacture or use crystalline materials in sectors ranging from the Chemical Industry, to Environment, Healthcare, Formulated Products, Oil and Gas, Water, Mining and Advanced Materials.
Industry: As indicated by our industrial collaborators in their letters of support, a greater understanding of crystallisation processes is required in a huge range of applications. The ability to generate specific crystal polymorphs is required in the field of nanomedicine (eg vaterite as soluble drug-delivery agents), while papers coated with aragonite rather than calcite exhibit superior brightness, opacity and strength. Nucleants in washing detergent can reduce crystal deposition on clothing, while the remediation of buildings from weathering relies on crystallisation in porous media. We need to enhance the mechanical properties of building materials such as gypsum, while controlling crystallisation on surfaces is critical to issues as diverse as scale inhibition in heating systems and oil wells, and bone and tooth regeneration. These are all topics addressed in the research programme, where direct collaboration with our industrial partners Proctor and Gamble, Unilever, BP, Lubrizol and Saint Gobain will ensure that technological and economic impact are achieved. Members of the consortium have had considerable success in translating research results to end-users and this embeds valuable experience in the Programme and provides a model that could be followed.
Training: The training and mentoring of early-stage researchers is an essential part of the project. They will acquire a wide range of technical and transferable skills, which will be of value both during this project and in their subsequent careers in industry and academia. We also place a high priority on training in communication and engagement with end users. The project will improve staff skills (science and team-working) via collaboration, through visits and secondments to our academic collaborators and through interactions with industry partners.
Dissemination: Industry and interest groups will be engaged via multiple channels, including our annual "Crystallisation day", specialist workshops, reports to learned societies and policy-makers, through social media, briefing documents and our web presence. We will promote new opportunities for academic-academic and academic-industry partnerships, beyond the consortium and partners. In this way we will seek to build a network for the benefit of the UK as a whole in the short, medium and long-terms. Our results will be published (after IP protection if necessary) in leading journals and presented at national and international scientific meetings. Papers will be available on the open access portals of our institutions and we will archive data in accordance with RCUK best practice.
Outreach and Advocacy: Crystallisation lends itself to impact through public engagement and outreach. All our institutions have well-established outreach programmes including annual Festivals of Science and presentations for teachers/sixth formers and all have dedicated academic outreach officers. We will also exploit all opportunities available to promote advocacy for the Engineering and Physical Sciences within the UK. As the project embodies fundamental interdisciplinary science whilst also being strongly linked to issues of major public interest such as healthcare and the environment, it will be an excellent vehicle for engaging decision makers. We will also empower our industrial partners to act as advocates for the promotion of the project's science and activities.
Industry: As indicated by our industrial collaborators in their letters of support, a greater understanding of crystallisation processes is required in a huge range of applications. The ability to generate specific crystal polymorphs is required in the field of nanomedicine (eg vaterite as soluble drug-delivery agents), while papers coated with aragonite rather than calcite exhibit superior brightness, opacity and strength. Nucleants in washing detergent can reduce crystal deposition on clothing, while the remediation of buildings from weathering relies on crystallisation in porous media. We need to enhance the mechanical properties of building materials such as gypsum, while controlling crystallisation on surfaces is critical to issues as diverse as scale inhibition in heating systems and oil wells, and bone and tooth regeneration. These are all topics addressed in the research programme, where direct collaboration with our industrial partners Proctor and Gamble, Unilever, BP, Lubrizol and Saint Gobain will ensure that technological and economic impact are achieved. Members of the consortium have had considerable success in translating research results to end-users and this embeds valuable experience in the Programme and provides a model that could be followed.
Training: The training and mentoring of early-stage researchers is an essential part of the project. They will acquire a wide range of technical and transferable skills, which will be of value both during this project and in their subsequent careers in industry and academia. We also place a high priority on training in communication and engagement with end users. The project will improve staff skills (science and team-working) via collaboration, through visits and secondments to our academic collaborators and through interactions with industry partners.
Dissemination: Industry and interest groups will be engaged via multiple channels, including our annual "Crystallisation day", specialist workshops, reports to learned societies and policy-makers, through social media, briefing documents and our web presence. We will promote new opportunities for academic-academic and academic-industry partnerships, beyond the consortium and partners. In this way we will seek to build a network for the benefit of the UK as a whole in the short, medium and long-terms. Our results will be published (after IP protection if necessary) in leading journals and presented at national and international scientific meetings. Papers will be available on the open access portals of our institutions and we will archive data in accordance with RCUK best practice.
Outreach and Advocacy: Crystallisation lends itself to impact through public engagement and outreach. All our institutions have well-established outreach programmes including annual Festivals of Science and presentations for teachers/sixth formers and all have dedicated academic outreach officers. We will also exploit all opportunities available to promote advocacy for the Engineering and Physical Sciences within the UK. As the project embodies fundamental interdisciplinary science whilst also being strongly linked to issues of major public interest such as healthcare and the environment, it will be an excellent vehicle for engaging decision makers. We will also empower our industrial partners to act as advocates for the promotion of the project's science and activities.
Organisations
- University of Leeds (Lead Research Organisation)
- University of Copenhagen (Collaboration)
- University of Manchester (Collaboration)
- Tata Steel (United Kingdom) (Collaboration)
- University of Warwick (Collaboration)
- Quorum Review- Independent Review Board (Collaboration)
- Polytechnic University of Milan (Collaboration)
- BP (United States) (Project Partner)
- Procter & Gamble (United States) (Project Partner)
- Lubrizol Ltd (Project Partner)
- Directed Assembly Network (Project Partner)
- Saint-Gobain (United Kingdom) (Project Partner)
Publications
Bentley CL
(2022)
High-Resolution Ion-Flux Imaging of Proton Transport through Graphene|Nafion Membranes.
in ACS nano
Besselink R
(2020)
Mechanism of Saponite Crystallization from a Rapidly Formed Amorphous Intermediate
in Crystal Growth & Design
Blow K
(2023)
Understanding the impact of ammonium ion substitutions on heterogeneous ice nucleation
in Faraday Discussions
Blow KE
(2021)
The seven deadly sins: When computing crystal nucleation rates, the devil is in the details.
in The Journal of chemical physics
Broad A
(2020)
Magnesium-rich nanoprecipitates in calcite: atomistic mechanisms responsible for toughening in Ophiocoma wendtii.
in Physical chemistry chemical physics : PCCP
Broad A
(2022)
Calcite Kinks Grow via a Multistep Mechanism.
in The journal of physical chemistry. C, Nanomaterials and interfaces
Chen B
(2021)
Artificial Synapse: Spatiotemporal Heterogeneities in Dopamine Electrochemistry at a Carbon Fiber Ultramicroelectrode.
in ACS measurement science au
Darkins R
(2022)
Nonequilibrium capture of impurities that completely block kinks during crystal growth
in Journal of Crystal Growth
Darkins R
(2022)
Calcite Kinetics for Spiral Growth and Two-Dimensional Nucleation
in Crystal Growth & Design
Darkins R
(2023)
Accelerating Solvent Dynamics with Replica Exchange for Improved Free Energy Sampling
in Journal of Chemical Theory and Computation
Darkins R
(2022)
Critical Step Length as an Indicator of Surface Supersaturation during Crystal Growth from Solution.
in Crystal growth & design
Di Pasquale N
(2023)
Constant chemical potential-quantum mechanical-molecular dynamics simulations of the graphene-electrolyte double layer.
in The Journal of chemical physics
Dietrich F
(2023)
Machine Learning Nucleation Collective Variables with Graph Neural Networks
in Journal of Chemical Theory and Computation
Dunn T
(2023)
Universality of Hair as a Nucleant: Exploring the Effects of Surface Chemistry and Topography
in Crystal Growth & Design
Finney A
(2021)
Electrochemistry, ion adsorption and dynamics in the double layer: a study of NaCl(aq) on graphite
in Chemical Science
Finney A
(2023)
Molecular simulation approaches to study crystal nucleation from solutions: Theoretical considerations and computational challenges
in WIREs Computational Molecular Science
Finney A
(2023)
A variational approach to assess reaction coordinates for two-step crystallization
in The Journal of Chemical Physics
Finney AR
(2022)
Multiple pathways in NaCl homogeneous crystal nucleation.
in Faraday discussions
Freeman C
(2023)
The transformation of amorphous calcium carbonate to calcite and classical nucleation theory
in Journal of Crystal Growth
Freeman HM
(2019)
Beam-induced oxidation of mixed-valent Fe (oxyhydr)oxides (green rust) monitored by STEM-EELS.
in Micron (Oxford, England : 1993)
Galloway J
(2023)
Electron transparent nanotubes reveal crystallization pathways in confinement
in Chemical Science
Garcia N
(2019)
Simulation of Calcium Phosphate Prenucleation Clusters in Aqueous Solution: Association beyond Ion Pairing
in Crystal Growth & Design
Green D
(2021)
Dichroic Calcite Reveals the Pathway from Additive Binding to Occlusion
in Crystal Growth & Design
H Perez JP
(2020)
Direct Visualization of Arsenic Binding on Green Rust Sulfate.
in Environmental science & technology
Hövelmann J
(2019)
Struvite Crystallisation and the Effect of Co2+ Ions
in Minerals
Ihli J
(2020)
Ptychographic X-ray tomography reveals additive zoning in nanocomposite single crystals.
in Chemical science
Ilett M
(2020)
Application of automated electron microscopy imaging and machine learning to characterise and quantify nanoparticle dispersion in aqueous media.
in Journal of microscopy
Ilett M
(2020)
Analysis of complex, beam-sensitive materials by transmission electron microscopy and associated techniques.
in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences
Ilett M
(2023)
In situ electron microscopy techniques for nanoparticle dispersion analysis of commercial sunscreen
in Journal of Nanoparticle Research
Innocenti Malini R
(2019)
Interaction of stable aggregates drives the precipitation of calcium phosphate in supersaturated solutions
in CrystEngComm
Karmakar T
(2023)
Non-Equilibrium Modeling of Concentration-Driven processes with Constant Chemical Potential Molecular Dynamics Simulations
in Accounts of Chemical Research
Kim YY
(2019)
Hydroxyl-rich macromolecules enable the bio-inspired synthesis of single crystal nanocomposites.
in Nature communications
Kundu S
(2021)
Breaking universality in random sequential adsorption on a square lattice with long-range correlated defects.
in Physical review. E
Le T
(2023)
Mesoscale Simulations Reveal How Salt Influences Clay Particles Agglomeration in Aqueous Dispersions
in Journal of Chemical Theory and Computation
Levenstein MA
(2022)
Serial small- and wide-angle X-ray scattering with laboratory sources.
in IUCrJ
Li L
(2023)
Nucleation of Biomolecular Condensates from Finite-Sized Simulations
in The Journal of Physical Chemistry Letters
Mandal D
(2022)
Kinetic control of competing nuclei in a dimer lattice-gas model.
in The Journal of chemical physics
| Description | TA1: Homogeneous nucleation • We have built a minimal-physics model which captures nucleation from solution in the presence of impurities. The model reveals a surfactant-like mechanism for enhancing nucleation within certain parameter regimes. We are in the process of conducting a full parameter sweep to map out additional behaviours such as solute immobilisation and solution stability shifts. • An additional generic minimal-physics model with nucleation of competing phases has been developed. Tuning of this model yields a system in which the nucleation product is highly sensitive to conditions, allowing us to observe both stable and long-lived metastable phases under similar conditions and with minimal computational expense. We have shown how populations of nuclei can be determined by the diffusivity of solute species and will now explore additional mechanisms of control in TA2, TA4 and TA6. • We are addressing a limitation of the above models which restricts us to the limit of fast solute transport from the surrounding medium. Early results show that canonical molecular simulations which neglect solute depletion may be leading to highly spurious results incorrect by several orders of magnitude. • We have developed a correlated methodology for experimentally studying nucleation in the electron microscope via the consideration of the different issues affecting liquid cell transmission electron microscopy (LCTEM), cryo TEM and conventional TEM on dried samples at various timepoints. • We have investigated the role of disordered intermediates - emerged as key features of the electrical double layer in graphite/water interfaces (see TA3) - in the nucleation of NaCl from aqueous solution with atomistic simulations. Building on configurational sampling obtained with well tempered metadynamics we have collected independent unbiased trajectories sampling the growth and dissolution of NaCl clusters with a wide range of internal structures. We used this information to build a Markov State Model able to reveal the existence of multiple pathways to nucleation, suggesting that pathways involving disordered intermediates might be favourable in supersaturated systems below the spinodal decomposition regime. • An analysis of data using the first nucleation theorem has shown that, in typical experimental conditions, calcium carbonate nucleates through the formation of critical nuclei consisting of only a few formula units. Such nuclei are too small to be classified as a particular polymorph, suggesting that bulk structure selection takes place later on, during stable growth. TA2: Polymorph Selection • We have calibrated a liquid cell transmission electron microscope (LCTEM) holder to study crystallisation and phase transformation at the micro/nanoscale in-situ and in real time. The effects of electron beam exposure have been modelled using chemical speciation software and the effects of the confined reactor volume on kinetics have been characterised. We have developed a work flow whereby LCTEM is correlated by cryo-TEM studies which do not suffer from either confinement effects and where beam damage is minimised. • A repeatable LCTEM study of the real time hydration of calcium sulphate (bassanite nanorods to gypsum needles) has been undertaken and hydration appears to be complete within a few minutes for the setup used via dissolution-repreciiptation. This has been benchmarked against time-resolved cryoTEM. The study is now being extended to the direct crystallisation of gypsum from solution and initial results suggest that bassanite per se is not an intermediate in the crystallisation process . • Polymorph selection for the calcium carbonate system has been experimentally investigated as a function of supersaturation, temperature and calcium: carbonate molar ratios. We have experimental evidence from cryoTEM for a dense liquid phase pre-cursor prior to the formation of amorphous calcium carbonate and subsequently crystalline polymorphs. • We have shown that cationic polyamines ranging from small molecules to large polyelectrolytes can exert exceptional control over calcium carbonate polymorph, promoting aragonite nucleation at extremely low concentrations, but suppressing its growth at high concentrations, such that calcite or vaterite form. The aragonite crystals form via particle assembly, giving nanoparticulate structures analogous to biogenic aragonite, and subsequent growth yields stacked aragonite platelets comparable to structures seen in developing nacre. This mechanism of polymorph selectivity is captured in a theoretical model based on these competing nucleation and growth effects, and is completely distinct from the activity of magnesium ions, which generate aragonite by inhibiting calcite. • Using computational simulations, we have considered the effect of the calcium: carbonate ratio on polymorph selection and observed reduced proto-nuclei formation at certain concentrations of carbonate. We have also examined the role of water ordering at interfaces and how this might encourage proto-nuclei formation. • We have developed a forcefield for use in nitrate systems that correctly models both the structures of all the alkali metal halides and also gets the correct relative energetic stabilities for their various phases. This forcefield has been extended to include interactions with water so we can examine nucleation of nitrate systems. • A new methodology for generating the interfacial free energy of crystals in solution has been produced. This is to be incorporated into the LAMMPS code by their developers. This approach allows us to consider the importance of entropy in the stability of surfaces and is applicable for many types of interface, including surfaces, aqueous interfaces and grain boundaries. We have applied this to sulphate systems to understand the relative stabilities of the different sulphate nuclei. Work has begun using our computational tools to examine the intergrowth of sulphate surfaces seen in experiments and how their structure may evolve during this process. TA3: Surface-Directed Crystallisation • TA3 seeks to advance understanding of how surfaces direct crystallisation, based on their effect on local concentration and potential gradients. A key advance has been the use of electrokinetic mixing inside nanopipettes to induce, and simultaneously measure, precipitation where the electric field can be controlled. Applied to both aqueous and non-aqueous systems, various solids (inorganic, metal-organic framework, organic) have been formed by selective use of applied voltage and then characterised with electron microscopy. Finite element (FEM) simulation confirmed the role of the field in the selectivity. Parallel studies have revealed the nature of the nanoscale mixing process in exquisite detail for future applications. • Crystal growth kinetics are determined by the interfacial supersaturation which depends on the interplay between mass transport from the bulk solution to crystal surface and surface kinetics. The critical step length at screw dislocation growth hillocks has been identified and proven to be a sensitive yardstick for interfacial supersaturation, by analysis of atomic force microscopy (AFM) images of calcite growth and the development of a FEM model for mass transport in an AFM fluid cell. The analysis should be generally applicable to any crystal growth process and in-situ technique where steps or hillocks are visualised. The speciation model used for these studies has been translated to other areas, including the electroreduction of CO2, which is of intense interest for future energy systems. • Atomic level detail of the interfacial region is revealed in molecular dynamics simulations of the graphite-sodium chloride interface. For the first time, the rich layered structure of the interface is used to explain trends in the differential capacitance that contradict the prevailing Gouy-Chapman-Stern model. This work provides a platform to understand how electrochemical interfaces can be tailored to promote crystal growth. • The effect of surface (applied) potential on crystallisation at surfaces has been explored in several systems. An impinging jet flow cell has been set up to allow control over mass transport and composition at crystallising interfaces, with crystallization monitored by: optical microscopy, quartz crystal microbalance measurements or attenuated total reflection - infrared (ATR-IR) spectroscopy. • We have introduced interference reflection microscopy (IRM) as a powerful in-situ visualisation method for following crystallization, with the possibility of monitor 3D growth kinetics at several crystals within a population simultaneously. • A combined scanning electrochemical cell microscopy (SECCM) - IRM technique has been designed built and tested that allows multiple crystallisation experiments in the confined droplet at the end of a nanopipette in meniscus contact with a surface. This is being applied to study the effect of applied potential on the nucleation and growth of calcium carbonate and gypsum at self-assembled monolayers (SAMs) on gold electrodes. A dual channel SECCM pipette is employed to execute nanoscale mixing on demand via an applied electric field. • The apparent qualitative discrepancy between simplified mesoscopic models of mass transfer at the solid/liquid interface, and atomistic simulations of electrolyte solutions at exchanging and non-exchanging surfaces have been examined, highlighting how non-idealities should be incorporated in mean field models to obtain consistent models across scales, informed by atomistic simulations. TA4: Nucleant-Controlled Crystallisation • Our simulations have focused on the role of surface defects. We have built different surface defects into self-assembled monolayers (SAMs) and examined their interaction with water and calcium carbonate. Our results have demonstrated that the surface defects may interact differently with the ions due to added flexibility of the SAMs caused by under-bonding. This couples with additional changes to water organisation and dynamics in these areas which may affect the ability of ions to move freely across the surface. Hence surface defects can act as centres both to generate localised high ion concentrations and to stimulate and stabilise clusters. The key role of these surface defects helps explain how classical nucleation theory works in heterogeneous systems. Although the basic model expects nucleation to occur freely across the surface, our work indicates the importance of the limited numbers of sites that are available as nucleation points (the equivalent of the pre-nucleation clusters sometimes proposed in homogeneous nucleation). • The efficacy of heterogeneous nucleants is dependent not only on surface chemistry, but also surface topography. We are investigating nucleation on substrates exhibiting surface cracks and have demonstrated that these can provide favourable sites for the nucleation of crystals including calcium carbonate. We have also demonstrated that we can place cracks into a surface and thus intentionally programme where crystals form. • Hair is used as a nucleant in technologically important crystallisation processes. Preventing the deposition of calcium mineral scale on hair is an important consideration for the efficacy of products in the hair care industry. We have characterised the surface chemistry and local charge on hair (with scanning ion conductance microscopy), using techniques developed in TA3, and investigated correlations with the crystallisation of both potassium nitrate and calcium carbonate, to reveal how local variations in the properties of hair (human and animal) effect crystallisation. • We have been exploring the use of surface topography to control crystal nucleation and growth. Thin films of metal are deposited on PDMS, whose flexibility causes the metal film to crack. Calcium carbonate deposited on these substrates almost exclusively grows in the cracks, where this effect can be enhanced by functionalising the substrate with self assembled monolayer (SAMs). Detailed investigations have been carried out on the influence of the crack dimensions and surface chemistry, and the early stages of crystallisation within the surface cracks has been explored. • We have built systems for simulating nucleant effects with a variety of charges and topologies in simulation and combined this with constant chemical systems so we can determine the "effective" concentration at the surface at variety of experimental conditions. TA5: Additive-Directed Crystal Growth • TA5 seeks to develop a microscopic understanding of how the presence of additional species in the host solution and the crystal can affect the kinetics of growth, and influence structural and morphological outcomes. • We have developed a comprehensive set of mesoscopic models to address various aspects of the growth of calcite in the presence of additives. One of the fundamental insights is that the competition between step nucleation at screw dislocations and from 2-d island formation can be shifted in favour of the latter through the inhibition of step propagation brought about by additives, leading to blunted crystalline morphologies with the creation of piled-up edges that form pseudo-faces. A second insight is that boundary layer diffusion control of the kinetics is often present in crystal growth experiments, and that this brings about size-dependent shifts in morphology. • Models of the kinetics of pseudo-face creation and roughening have been constructed using a set of modified Becker-Döring rate equations. The effects arise from diffusion-driven step aggregation followed by preferential additive attachment at multisteps leading to their relative immobilisation. Further work is ongoing to understand the formation of concave and convex pseudofaces. • A complete set of calculations of the free energy surfaces characterising ion attachment at kink sites in calcite has been undertaken. A new insight is that ions can initially attach in elevated positions relative to the lattice site, and are brought down into place only upon attachment of the next ion. Furthermore, such a multistep kink propagation mechanism seems to present no significant free energy barriers, neither from dehydration nor reordering, suggesting that diffusion to the surface is the more important rate determining step in the kinetics. • Metadynamics in combination with Hamiltonian replica exchange has been tested as an efficient method for computing free energy profiles for species attachment to surfaces. It appears to be a more powerful approach as an alternative to metadynamics defined by rigid choices of collective variables. • Efficient parallel computation of surface growth modelled by kinetic Monte Carlo has been explored using GPU resources. Novel ideas for the mapping of a large surface onto semi-independent tiles allows a speed-up of several orders of magnitude in some cases. Extension to three dimensions and further application is under development. • Amino acid assisted occlusion of dye molecules into calcite has been investigated in a wide ranging set of experiments, suggesting several mechanisms might be operating. It has been suggested that the Asp amino acid disrupts the hydration layer at the surface, facilitating attachment of the much larger dye molecules. Another suggestion is that the amino acids bind to the dye in solution and chaperone the latter into an occluded position. • Ptychographic X-ray computed tomography (PXCT) was, used to visualise the 3D internal structures of micron-scale nanocomposite calcite crystals containing diblock copolymer worms and vesicles. The results provided valuable information about the distribution of the polymer nano-objects within entire crystals at nanometre spatial resolution and revealed how occlusion is governed by factors including the supersaturation and calcium concentration. • Crystallisation has been studied in the presence of coloured dye molecules, where this has enabled us to explore the pathway from adsorption on the crystal surface to occlusion, and to investigate how the solvent influences occlusion. TA6: Crystallisation in Confinement • We have developed an imaging-based strategy that exploits confinement effects to track the evolution of a population of individual crystals in 3D, and use it to characterize complex crystallization processes. Focusing on the hotly-debated calcium sulphate system, precipitation is carried out within nanoporous media in which the crystals are fixed in position and develop slowly. The evolution of the size, shape and polymorphs of the crystals are then tracked in situ using synchrotron X-ray computed tomography and diffraction computed tomography. Our study reveals formation of an amorphous phase and long-lived bassanite (CaSO4·0.5H2O) in aqueous solution at room temperature, and importantly demonstrates that the thermodynamically stable phase gypsum (CaSO4·2H2O) can precipitate by different pathways according to reaction environment. This confirms current hypotheses about the transformation of the amorphous phase into crystalline forms of calcium sulphate. • Track-etched (TE) membrane pores with diameters between 500 and 10 nm are used either uncoated, or after coating with a thin film of amorphous TiO2. Gypsum formed in pores >200 nm, whereas bassanite formed in pores <100 nm in diameter and anhydrite in 10 nm pores. Over time, the bassanite formed in the uncoated pores turned to gypsum, but the bassanite formed within the TiO2 coated membranes was stable for over 3 months. Dissolution of the TiO2-coated membranes released TiO2 nanotubes containing the developing calcium sulphate crystallites. These act as electron-transparent test tubes which allowed the evolution of the nanoparticles in confinement to be studied. • We are investigating the influence of the confining surface on crystallisation. This is being achieved using gold-coated cylindrical pores, where we vary the surface charge by applying a potential and investigate the crystals generated within the pores as a function of the solution conditions, pore size and surface potential, and interpret the data obtained with parallel calculations of the double layer structure and mass transport. • Graphene nanomaterials (GNMs) are being explored as novel nucleants that can enhance nucleation rates and even direct crystal polymorph. The beauty of GNMs is that they are electron transparent and their conformation can be readily explored using cryo electron tomography. This system therefore enables us to examine how crystals form in situ within the confines of the wrinkles and folds of the GNMs. Experimental results are being complemented by modelling studies, where we can directly employ the experimental data on the conformation of the GNMs in the simulations. • We have investigated the behaviour of the multi-species model from TA1 using system size as a proxy for confinement. We have demonstrated that the most easily nucleated phase can be controlled with system size. A prototype lattice-Boltzmann implementation is now being coupled to our model to allow us to quantity this effect under semi-open conditions represent confinement experiemnts. • Following an analysis of nucleation rate data for calcium carbonate, it has been concluded that polymorph selection does not take place at the time of critical cluster formation. The clusters are too small to possess the bulk properties or crystalline order of the available polymorphs. Instead, selection will take place during the stable growth of an amorphous cluster, within a time frame where it is still small enough for thermal fluctuations to allow the adoption of a variety of different structures. This hypothesis holds promise in the interpretation of experimental data on polymorph selection in confined geometries, where growth occurs in parallel with cluster attachment and detachment from surfaces, which might provide an intermittent templating effect that would promote a more adaptable, and potentially more metastable, polymorph. |
| Exploitation Route | The key impacts of the proposed work relate to the development of new understanding, and from these methods to control inorganic crystallisation under conditions relevant to real world applications. Specifically, we expect to deliver outcomes including the ability to: (1) identify well-defined reaction conditions for generating specific crystal polymorphs; (2) select nucleants that promote crystallisation of selected compounds; (3) use confinement to control crystallisation; (4) design surfaces that can promote (or prevent) crystallisation; (5) select or design additives that give crystals with desired shapes and sizes; (6) select additives that inhibit unwanted crystallisation and (7) create composite crystals with tuneable properties. The range of beneficiaries is therefore extremely broad, and includes all of those who research, manufacture or use crystalline materials in sectors ranging from the Fine Chemical, Pharmaceutical, Formulated Products, Oil and Gas, Water, Mining/ Separation and Advanced Materials. |
| Sectors | Agriculture, Food and Drink,Chemicals,Environment,Manufacturing, including Industrial Biotechology,Culture, Heritage, Museums and Collections |
| URL | https://realworldcrystals.leeds.ac.uk/ |
| Description | Dr. Helen Freeman has been awarded a Parliamentary Academic Fellowship at the Parliamentary Office of Science and Technology. From January to October 2021 she will work 2 days per week writing a research briefing for MPs and Peers titled NetZero: Decarbonising Construction, with a focus on the role of low carbon materials for a sustainable transition. Details here: https://post.parliament.uk/approved-net-zero-and-decarbonising-construction/. This secondment is funded by the QR-SPF (£12,000). |
| Geographic Reach | National |
| Policy Influence Type | Implementation circular/rapid advice/letter to e.g. Ministry of Health |
| URL | https://post.parliament.uk/approved-net-zero-and-decarbonising-construction/ |
| Description | 3D Nanoscale chemical analysis: a FIBSEM-SIMS facility optimised for soft and composite materials |
| Amount | £1,726,123 (GBP) |
| Funding ID | EP/V028855/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 07/2021 |
| End | 06/2025 |
| Description | Core Equipment at the University of Leeds |
| Amount | £549,999 (GBP) |
| Funding ID | EP/T024488/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 02/2020 |
| End | 08/2021 |
| Description | Cryogenic electron microscopy for native state analysis of nanoparticles in liquids |
| Amount | £196,879 (GBP) |
| Funding ID | EP/R043388/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 09/2018 |
| End | 02/2021 |
| Description | EPSRC IAA 2022-2025 (High throughput screening platform...) |
| Amount | £24,401 (GBP) |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 04/2023 |
| End | 09/2023 |
| Description | Flow-Xl: A New UK Facility for Analysis of Crystallisation in Flow Systems |
| Amount | £1,129,048 (GBP) |
| Funding ID | EP/T006331/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 01/2020 |
| End | 01/2022 |
| Description | Physicochemical processes in droplets |
| Amount | £45,000 (GBP) |
| Organisation | Syngenta International AG |
| Department | Syngenta Crop Protection |
| Sector | Private |
| Country | United Kingdom |
| Start | 10/2021 |
| End | 09/2025 |
| Title | Dataset for 'Serial Small- and Wide-Angle X-ray Scattering with Laboratory Sources' |
| Description | This dataset contains measurements used in the paper, 'Serial Small- and Wide-Angle X-ray Scattering with Laboratory Sources' from the journal, IUCrJ (doi: 10.1107/S2052252522007631). Included are the raw SAXS, WAXS, and XRD patterns used in the evaluation of different samples, sample environments, and X-ray scattering instruments. From these data, the authors determined that it is feasible to perform serial SAXS/WAXS analysis of materials using laboratory X-ray sources with the aid of micro- and milli-fluidic sample environments. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://archive.researchdata.leeds.ac.uk/1010/ |
| Description | Collaboration with Andre Geim and Marcelo Lozada-Hidalgo (University of Manchester) |
| Organisation | University of Manchester |
| Department | National Graphene Institute |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | We applied the state of the art SECCM technique to understand the charge transfer properties of suspended graphene, in particular identifying sites for proton transport |
| Collaborator Contribution | Supplied well characterised devices and samples, deep engagement in the science and data, including modelling through additional collaboration. |
| Impact | A paper is under review/revision. |
| Start Year | 2021 |
| Description | Collaboration with WMG, Warwick |
| Organisation | University of Warwick |
| Department | Warwick Manufacturing Group |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Through the award of this funding, and the unique experimental capability we will establish, we are creating new collaborations with WMG (Geoff West and Mel Loveridge) to do some pump priming experiments. |
| Collaborator Contribution | The link is through Pat Unwin, Warwick Chemistry. |
| Impact | Just started. |
| Start Year | 2020 |
| Description | Copenhagen-Sheffield Collaboration |
| Organisation | University of Copenhagen |
| Country | Denmark |
| Sector | Academic/University |
| PI Contribution | Simulations exploring the binding of molecules at polar surfaces. |
| Collaborator Contribution | Costs for travel and subsistence. Atomic force microscopy experiments. HPC facilities in Copenghagen University. |
| Impact | New research. PhD award Dr Beatriz Fonseca 2022 Publication DOI 10.1016/j.chemphys.2022.111602 |
| Start Year | 2019 |
| Description | Quorum Cryo-liftout |
| Organisation | Quorum Review- Independent Review Board |
| Country | United States |
| Sector | Private |
| PI Contribution | Collaboration with company Quorum on in-situ liftout of frozen TEM samples |
| Collaborator Contribution | Collaboration with company Quorum on in-situ liftout of frozen TEM samples |
| Impact | none so far |
| Start Year | 2017 |
| Description | Warwick - Politecnico di Milano collaboration |
| Organisation | Polytechnic University of Milan |
| Country | Italy |
| Sector | Academic/University |
| PI Contribution | Expertise in umbrella sampling and other rare event sampling techniques in lattice Monte Carlo. Link to problems in simulations of open chemical systems in the context of nucleation from solution. |
| Collaborator Contribution | Acceleration of simulations using the n-fold way Monte Carlo technique and the implementation of this within contexts of relevance to the simulating nucleation under confinement. |
| Impact | No outputs yet. |
| Start Year | 2023 |
| Description | iCASE Award on corrosion |
| Organisation | TATA Steel |
| Country | India |
| Sector | Private |
| PI Contribution | This project is focused on the corrosion of battery casings and coatings and will make use of the glovebox-scanned electrochemical probe microscope set up that we are setting up for "Quantitative imaging of Multi-Scale Dynamic Phenomena at Electrochemical Interfaces" |
| Collaborator Contribution | Pat Unwin is supervisor of the project and Geoff West (WMG, Warwick) is cosupervisor. |
| Impact | Recently started. |
| Start Year | 2019 |
| Description | 'Chalk to Chocolate' workshop at Famile Day, University of Warwick at end of British Association of Science Annual meeting |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | This was one of a number of demonstrations at a Family Day, which an estimated 800 people attended. This particular eveny reacjed several hundred people. |
| Year(s) Of Engagement Activity | 2019 |
| Description | 7 Science lessons with the RSC Spectroscopy in a Suitcase program |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | Ian McPherson (PDRA on the crystallisation programme grant) delivered 7 Science lessons with the RSC Spectroscopy in a Suitcase program |
| Year(s) Of Engagement Activity | 2019 |
| Description | After school club event on crystals |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | Ian McPherson organised an after school club event on crystals with other researchers from the University of Warwick Electrochemistry Group |
| Year(s) Of Engagement Activity | 2019 |
| Description | Annual Royal Microscopical Society School in Elecron Microscopy - every Spring or Summer 2008 onwards |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Week long Training School for users of the technique |
| Year(s) Of Engagement Activity | 2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020,2021 |
| Description | Be Curious Science Outreach event |
| Form Of Engagement Activity | Participation in an open day or visit at my research institution |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Schools |
| Results and Impact | Microscopy Talk, Activities and Display at Be Curious Festival at University of Leeds, Annual event every March |
| Year(s) Of Engagement Activity | 2016,2017,2018,2019,2020 |
| URL | http://www.leeds.ac.uk/info/4000/around_campus/460/be_curious_festival-about_leeds_and_yorkshire |
| Description | Blog on science communication from team member Peter Morris (associated PhD student) |
| Form Of Engagement Activity | A magazine, newsletter or online publication |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | Blog by associated PhD student, Peter Morris, on communicating research to policymakers |
| Year(s) Of Engagement Activity | 2019 |
| URL | https://www.wiley.com/network/researchers/latest-content/5-tips-for-communicating-research-to-policy... |
| Description | Co-organisation of Royal Society Discussion Meeting, Dynamic in-situ microscopy relating structure and function |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Fast-track discussion meeting organised by Dame Pratibha Gai FREng FRS, Professor Edward Boyes, Professor Rik Brydson and Professor Richard Catlow FRS. October 21-22 2019 This meeting evidenced and advanced development in dynamic in-situ environmental electron, scanning probe, optical and fast time resolved microscopy and computer modelling studies of vital interest in the chemical, physical and life sciences, underpinning technologies of high commercial and societal value. It focused on the pivotal role of imaging and spectroscopy for dynamic processes across the sciences to access previously invisible aspects of real world processes. An accompanying journal issue for this meeting was published in Philosophical Transactions of the Royal Society A. |
| Year(s) Of Engagement Activity | 2019 |
| URL | https://royalsociety.org/science-events-and-lectures/2019/10/in-situ-microscopy/ |
| Description | Concluding Remarks, Next Generation Nanoelectrochemistry Faraday Discussion, Dec 2021 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | I was invited to give Concluding Remarks, Next Generation Nanoelectrochemistry Faraday Discussion, Dec 2021. The meeting was held online and reached a large international audience. I summarised the key developments from the meeting, placing the work in a historical context. I further used this opportunity to predict how the field of nanoelectrochemistry may develop in the future. |
| Year(s) Of Engagement Activity | 2021 |
| Description | Distinguished Lecture, iNano, Aarhus |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Postgraduate students |
| Results and Impact | Invited lecture as part of the iNano Distinguished Lecture series, leading to dissemination of our activities in SECCM to a diverse audience in nanoscience. |
| Year(s) Of Engagement Activity | 2022 |
| Description | Exhibition of scientific images |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | Exhibition of images of crystals at the North Bar, Leeds |
| Year(s) Of Engagement Activity | 2019 |
| Description | Exhibition of scientific images |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | 6 week exhibition of images of crystals at the North Bar Leeds |
| Year(s) Of Engagement Activity | 2018,2019 |
| Description | Invited Keynote at 15th International Fischer Symposium, Kloster Seeon, Germany |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | I have an invited keynote at 15th International Fischer Symposium, Kloster Seeon, Germany. This meeting covers a broad range of electrochemistry and I was able to raise awarenes of our recent work on SECCM and high resolution electrochemical imagining. |
| Year(s) Of Engagement Activity | 2022 |
| Description | Invited Talk at Surface Energies Workshop |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Workshop to discuss the best practice for surface calculations. Invitation to Dr Stephen Yeandel due to impact of work on programme. Decisions made on informing the wider community and for future code development. Outcome was to use our new methodology in a future version of the main molecular dynamics code LAMMPs. |
| Year(s) Of Engagement Activity | 2022 |
| Description | Invited lecture - Nanoscience Days, Finland |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Postgraduate students |
| Results and Impact | I was an invited speaker at the longrunning Nanoscience Days conference, University of Jyväskylä. I was able to present our SECCM studies to a broad audience in nanoscience, raising awareness of our innovative methods. |
| Year(s) Of Engagement Activity | 2022 |
| Description | Invited lecture at AstraZeneca |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Industry/Business |
| Results and Impact | Lecture on our latest activities in crystallisation to AstraZeneca Scientists at Macclesfield (in person/online), Sweden (online) and USA (online) |
| Year(s) Of Engagement Activity | 2023 |
| Description | Presentation (Goldschmidt): Why no Aragonite? Polymorph selection in the early stages of calcium carbonate nucleation |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk given at international conference resulting in debate/discussion and collaboration |
| Year(s) Of Engagement Activity | 2018 |
| Description | Presentation (MRS): Simulating the effect of organic molecules on clustering in calcium carbonate and phosphate |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Presentation given at international meeting (MRS) giving rise todebate/discussion |
| Year(s) Of Engagement Activity | 2018 |
| Description | Presentation at Industry Day |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Industry/Business |
| Results and Impact | Presentation of the Programme Grant activity to members of the Industry Club (20 members) of the Institute of Process Research and Development at Weetwood Hall, Leeds |
| Year(s) Of Engagement Activity | 2022 |
| Description | Presentation of research at the East Midlands Big Bang Fair on Saturday 9th February. |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | Presentation of research at the East Midlands Big Bang Fair on Saturday 9th February, with over 4000 people attending. PM used the crystallisation of cocoa butter (aka chocolate) to explain polymorphism while IM discussed the importance of crystals in nature using the Meldrum group's impressive collection of biological crystals and scanning electron micrographs. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Royce Institute Workshop for PhD students |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Postgraduate students |
| Results and Impact | A three day residential workshop for 15-20 PhD students, particularly targeted at those in CDTs, to showcase (mostly) Royce facilities at Leeds. Basic structure was lectures then demonstrations. |
| Year(s) Of Engagement Activity | 2020 |
| Description | Scientific Organisation of Microscience Microscience Microscopy Congresses MMC2013, 2015, 2017, 2019, 2021 |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Attendance and presentation at conferences |
| Year(s) Of Engagement Activity | 2013,2015,2017,2019,2021 |
| URL | https://www.mmc-series.org.uk/ |
| Description | Workshop on Forcefield Development |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Workshop on theory of simulation methods to develop and use atomic forcefields. |
| Year(s) Of Engagement Activity | 2019 |
| URL | https://www.ccp5.ac.uk/node/305 |