Large-Scale Numerical Modeling of Melt and Solution Crystal Growth

Derby, Jeffrey J.; Chelikowsky, James R.; Sinno, Talid; Dai, Bing; Kwon, Younggoo; Lun, Lisa; Pandy, Arun; Yeckel, Andrew

doi:10.1063/1.2751913

Cited by 8 publications

(6 citation statements)

References 62 publications

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“…At the macroscopic level, the transport of solute (and impurities) toward the crystal−solution interface, the relative significance of convection and diffusion, and their interactions with crystal surfaces are relatively well-understood. 21 −28 These insights have allowed control over the development of growth instabilities and defects, 29−35,28,36−38 which can substantially alter the material properties. At the mesoscopic scale, crystal faceting is attributed to the high surface free energy of the crystal−solution interface, which explains the relative significance of the individual crystal faces in the equilibrium crystal shape through the surface free energy anisotropy.…”

Section: Introductionmentioning

confidence: 99%

Molecular Mechanisms of Hematin Crystallization from Organic Solvent

Olafson

Ketchum

Rimer

et al. 2015

Crystal Growth & Design

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Here, we employ n-octanol to elucidate the fundamental processes of hematin crystallization from an organic solvent, identify the operational mechanisms of growth, and determine the respective control parameters. The values of the enthalpy, entropy, and free energy of the crystal−solution equilibrium suggest that octanol may structure around the hematin solute molecules and along the crystal interface. Time-resolved in situ atomic force microscopy demonstrates that hematin crystal growth strictly follows classical layer growth mechanisms. Steps propagate by the attachment of solute molecules, described by a first-order chemical rate law. The molecules reach the steps via adsorption on the crystal surface, followed by surface diffusion, and the kinetic barriers of this pathway offer additional crystallization control strategies. Solute incorporation into steps from the adjacent lower and upper terraces is strongly asymmetric, with the lower terrace contributing the major solute amount. These findings provide a foundation for the rational design of hematin crystals that may find applications utilizing their high magnetic and optical anisotropy.

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Section: Introductionmentioning

confidence: 99%

Molecular Mechanisms of Hematin Crystallization from Organic Solvent

Olafson

Ketchum

Rimer

et al. 2015

Crystal Growth & Design

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“…Traditional crystallization procedures employ aqueous solutions where the corresponding mechanisms have been studied in detail at all relevant length scales: macroscopic, mesoscopic, and molecular. At the macroscopic scale we now understand the transport of solute and impurities toward the crystal–solution interface, − the relative significance of convection and diffusion, , and their effect on crystal surfaces that may provoke growth instabilities and engender defects. − At the mesoscopic scale, we attribute the faceted morphology of the majority of solution-grown crystals to the high surface free energy of the crystal–solution interface and explain the relative significance of the individual crystal faces in the equilibrium crystal shape through the surface free energy anisotropy. , At the molecular length scale, a fundamental property of water to form a three-dimensional network of hydrogen bonds, molded around solute molecules and along the crystal surface, has been identified as a major factor that determines the thermodynamic and kinetic parameters of solute incorporation into growth sites ,− and, correspondingly, the pathways and the rates of crystallization from aqueous solvents. − …”

Section: Introductionmentioning

confidence: 99%

Attraction between Permanent Dipoles and London Dispersion Forces Dominate the Thermodynamics of Organic Crystallization

Chakrabarti

Vekilov

2020

Crystal Growth & Design

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Organic crystallization controls natural and pathological processes and technologies to produce pharmaceuticals, fine chemicals, and electronic and optical devices. In contrast to water-based crystallization, the interactions and structures that govern crystallization from organic solvents remain elusive. We characterize the thermodynamics of crystallization of etioporphyrin I from five solvents selected to highlight the roles of several solute−solvent interactions; etioporphyrin I represents a class of molecules that arrange in low-symmetry crystals suitable for semiconductors and solar panels. To understand solvent structuring at the crystal interface and solvent−solute interactions in the solution, we employ as molecular probes the crystallization enthalpy and entropy, complemented by UV−vis absorption spectra of the solutions and electron microscopy and X-ray characterization of the crystal phases. The enthalpy and entropy trends reveal that solvent structuring insignificantly affects the solution thermodynamics owing to the weak solvent−solvent bonds. London dispersion forces between nonpolar groups of the solute and solvent take the place of the hydrophobic interactions common in aqueous solutions and, directed by attraction between permanent dipoles, dominate the solute−solvent interactions. Surprisingly, both hydrogen bonds and salt bridges contribute little to the solution thermodynamics. The emerging insight into the fundamental interactions in organic solutions illuminates the search for crystallization solvents that optimize the numbers, morphologies, and sizes of crystals of organic materials with appealing properties.

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“…The first one (front-tracking methods) is based on a multi-domain approach and defines a discrete moving surface to separate the interface between crystal and melt. The second category (diffuse-interface methods) is based on a single-domain approach where a system of momentum and energy equations is solved in the entire physical domain, and treats the interface as a region (mushy zone) of finite thickness across which physical properties vary rapidly but continuously from one bulk value to the other [7]. In contrast to the front-tracking methods, such as the widely used isotherm method, in a single-domain approach the thickness of the so-called mushy zone is very large compared to the width of a phase boundary of one or two layers of computational cells [8].…”

Section: Introductionmentioning

confidence: 99%

A Single-domain Approach to Simulate the Effect of Convective Flow on the Mushy-zone Structure in Czochralski Growth of Gadolinium Gallium Garnet Crystal

Faiez¹,

Rezaei²

2017

ujms

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A numerical study was carried out to describe the effect of the melt hydrodynamics on the crystallization front shape in the Czochralski growth of a semitransparent oxide crystal. In the present model calculation, the enthalpy-porosity method was used to solve the phase change problem with the convection due to buoyant, thermocapillary and centrifugal forces. It was shown that the rotationally-driven flow protrudes into the mushy zone when the crystal rotation rate was increased to a certain critical value corresponding to Gr/Re 2 =0.89 as the ratio between the intensity of buoyancy and forced convection flow in the melt. The ratio between the vertical and horizontal temperature gradients beneath the mushy zone was found to be decreased by increasing the crystal rotation rate. It was shown that the shape of the zone deforms abruptly when the ratio between the axial and radial temperature gradients decreased to the values smaller than the unity. The Burger's number condition was found to be violated in the case Gr/Re 2 <0.89, at which the onset of geostrophic instability is expected.

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Large-Scale Numerical Modeling of Melt and Solution Crystal Growth

Cited by 8 publications

References 62 publications

Molecular Mechanisms of Hematin Crystallization from Organic Solvent

Molecular Mechanisms of Hematin Crystallization from Organic Solvent

Attraction between Permanent Dipoles and London Dispersion Forces Dominate the Thermodynamics of Organic Crystallization

A Single-domain Approach to Simulate the Effect of Convective Flow on the Mushy-zone Structure in Czochralski Growth of Gadolinium Gallium Garnet Crystal

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