Multisite models to determine the distribution of kink sites adjacent to low-energy edges

Lovette, Michael A.; Doherty, Michael F.

doi:10.1103/physreve.85.021604

Cited by 27 publications

(44 citation statements)

References 27 publications

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“…For both solutes, the slowest growing face was exposed to the solution. Both solutes exhibit the same slowest growing face in all solvents considered, namely, face {110} in the case of urea and face {001̅} in the case of naphthalene. , The unfinished layer was cut along the slowest growing edge, i.e., for urea along the [001] direction and for naphthalene along the [010] direction. For each simulation setup, one edge of the surface comprises an unfinished row and the biased kink site.…”

Section: Computational Detailsmentioning

confidence: 99%

Solubility Prediction of Organic Molecules with Molecular Dynamics Simulations

Bjelobrk

Mendels

Karmakar

et al. 2021

Crystal Growth & Design

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We present a molecular dynamics simulation method for the computation of the solubility of organic crystals in solution. The solubility is calculated based on the equilibrium free energy difference between the solvated solute and its crystallized state at the crystal surface kink site. To efficiently sample the growth and dissolution process, we have carried out well-tempered metadynamics simulations with a collective variable that captures the slow degrees of freedom, namely, the solute diffusion to and adsorption at the kink site together with the desolvation of the kink site. Simulations were performed at different solution concentrations using constant chemical potential molecular dynamics, and the solubility was identified at the concentration at which the free energy values between the grown and dissolved kink states were equal. The effectiveness of this method is demonstrated by its success in reproducing the experimental trends of solubility of urea and naphthalene in a variety of solvents.

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Section: Computational Detailsmentioning

confidence: 99%

Solubility Prediction of Organic Molecules with Molecular Dynamics Simulations

Bjelobrk

Mendels

Karmakar

et al. 2021

Crystal Growth & Design

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“…As can be seen, the forward propagation of a step edge acts to complete the incomplete face layer. Kink sites are renewable upon attachment and furthermore are continually regenerated via thermal roughening[12,14,70,71] (seeFigure 3.2 (a) & (b)). Centrosymmetric crystals necessarily have the same kink-site interactions on each edge and face, but for non-centrosymmetric crystals each edge on each face can generally have multiple distinct kink sites containing different sets of interactions.…”

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confidence: 99%

“…At 0K the step edge is straight (a), while above 0K the propensity for rearrangement via thermal fluctuation leads kinks to exist at all times (b)[12,14,70,71]. The propagation length for addition of a row of growth units is a P , the width of a growth unit along the edge is a E and the number of sites between kinks is termed x 0 .…”

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confidence: 99%

A design aid for crystal growth engineering

Tilbury

Kim

et al. 2016

Progress in Materials Science

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With the highly competitive development of chemical and pharmaceutical industries, mastering crystal growth is becoming increasingly necessary. Modern industrial manufacturers place high importance on the ability to grow crystals with a specific habit using tailored operating conditions. A detailed understanding of crystal growth is, therefore, vital for researchers in crystallography and crystallization to respond and realize this objective. Various models to predict crystal shape in the literature are reviewed here. The most commonly adopted are usually non-mechanistic and limited in their predictive power and utility, especially for products of industrial interest. Mechanistic models offer far more potential for rational crystal design, but

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“…We eliminated four probable scenarios of apparent growth acceleration at high supersaturation: [13e] mesoscopic OZPN‐rich clusters [17,22] which provide additional OZPN molecules to the steps; inaccurate solubility, increasing kink density at higher supersaturation [8c,19, 23] and step pinning by impurities [21a]…”

Section: Resultsmentioning

confidence: 99%

How to Identify the Crystal Growth Unit

Verma

Warzecha

Chakrabarti

et al. 2021

Israel Journal of Chemistry

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The structure and composition of the crystal growth unit are of huge fundamental and practical consequence. We propose a method to identify the solute species that incorporates into the growth site on crystal surfaces, the kinks, which rests on the kinetics of the elementary reaction at the kinks. We use as model crystals olanzapine, an antipsychotic medication, and etioporphyrin I, a field-effect transistor. We combine time-resolved in situ atomic force microscopy with Raman and absorption spectroscopies, complemented by density functional theory and all-atom molecular dynamics modeling of the solutions. We show that the structure of the growth unit cannot be deduced neither from the solute oligomers nor from the crystal structure. Chemical kinetics analyses reveal that if the dominant solute species is the one that incorporates into the crystal growth sites, then the kinetics of layer growth complies with a monomolecular rate law. By contrast, if the crystal growth unit assembles from two units of the dominant solute form, a bimolecular rate law ensues. Solutions of both olanzapine and etioporphyrin I are dominated by solute monomers, which exist in equilibrium with a minority of dimers. Whereas numerous olanzapine crystal structures incorporate dimer motifs, etioporphyrin I crystals organize as stacks of monomers. Olanzapine crystal grow by incorporation of dimers. One of the studied face of etioporphyrin I grows by incorporation of the majority monomers, whereas the other one selects the minority dimers as a growth unit. The results highlight the power of the crystallization kinetics analyses to identify the growth unit and illuminate one of the most challenging issues of crystal growth.

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Multisite models to determine the distribution of kink sites adjacent to low-energy edges

Cited by 27 publications

References 27 publications

Solubility Prediction of Organic Molecules with Molecular Dynamics Simulations

Solubility Prediction of Organic Molecules with Molecular Dynamics Simulations

A design aid for crystal growth engineering

How to Identify the Crystal Growth Unit

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