Organic nanoparticles of malachite green with enhanced far-red emission: size-dependence of particle rigidity

The size-dependence of different physical properties of atomic clusters (by the example of binding energy, collision diameter, and static isotropic polarizability) is discussed.

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Energetic analysis of succinic acid in water droplets: insight into the size-dependent solubility of atmospheric nanoparticles

10.5194/acp-2020-1329 ◽

2021 ◽

Author(s):

Chuchu Chen ◽

Xiaoxiang Wang ◽

Kurt Binder ◽

Mohammad Mehdi Ghahremanpour ◽

David van der Spoel ◽

...

Keyword(s):

Succinic Acid ◽

Size Dependence ◽

Volume Ratio ◽

Size Dependent ◽

Bulk Volume ◽

Energetic Analysis ◽

Entropic Effect ◽

Dynamics Simulations ◽

Enhanced Surface ◽

Potential Of Mean Forces

Abstract. Size-dependent solubility is prevalent in atmospheric nanoparticles, but a molecular level understanding is still insufficient, especially for organic compounds. Here, we performed molecular dynamics simulations to investigate the size dependence of succinic acid solvation on the scale of ~1–4 nm with the potential of mean forces method. Our analyses reveal that the surface preference of succinic acid is stronger for a droplet than the slab of the same size, and the surface propensity is enhanced due to the curvature effect as the droplet becomes smaller. Energetic analyses show that such surface preference is primarily an enthalpic effect in both systems, while the entropic effect further enhances the surface propensity in droplets. On the other hand, with decreasing droplet size, the solubility of succinic acid in the internal bulk volume may decrease, imposing an opposite effect on the size dependence of solubility as compared with the enhanced surface propensity. Meanwhile, structural analyses, however, show that the surface to internal bulk volume ratio increases drastically, especially when considering the surface in respect to succinic acid, e.g., for droplet with radius of 1 nm, the internal bulk volume would be already close to zero for the succinic acid molecule.

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Energetic analysis of succinic acid in water droplets: insight into the size-dependent solubility of atmospheric nanoparticles

10.5194/egusphere-egu21-6415 ◽

2021 ◽

Author(s):

Chuchu Chen ◽

Xiaoxiang Wang ◽

Kurt Binder ◽

Mohammad Mehdi Ghahremanpour ◽

David van der Spoel ◽

...

Keyword(s):

Succinic Acid ◽

Size Dependence ◽

Volume Ratio ◽

Size Dependent ◽

Bulk Volume ◽

Energetic Analysis ◽

Entropic Effect ◽

Dynamics Simulations ◽

Enhanced Surface ◽

Potential Of Mean Forces

<p>Size-dependent solubility is prevalent in atmospheric nanoparticles, but a molecular level understanding is still insufficient, especially for organic compounds. Here, we performed molecular dynamics simulations to investigate the size dependence of succinic acid solvation on the scale of ~1-4 nm with the potential of mean forces method. Our analyses reveal that the surface preference of succinic acid is stronger for a droplet than the slab of the same size, and the surface propensity is enhanced due to the curvature effect as the droplet becomes smaller. Energetic analyses show that such surface preference is primarily an enthalpic effect in both systems, while the entropic effect further enhances the surface propensity in droplets. On the other hand, with decreasing droplet size, the solubility of succinic acid in the internal bulk volume may decrease, imposing an opposite effect on the size dependence of solubility as compared with the enhanced surface propensity. Meanwhile, structural analyses, however, show that the surface to internal bulk volume ratio increases drastically, especially when considering the surface in respect to succinic acid, e.g., for droplet with radius of 1 nm, the internal bulk volume would be already close to zero for the succinic acid molecule.</p>

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Size-dependent thermodynamic structural selection in colloidal crystallization

Science Advances ◽

10.1126/sciadv.aaw5912 ◽

2019 ◽

Vol 5 (9) ◽

pp. eaaw5912 ◽

Cited By ~ 5

Author(s):

Evan Pretti ◽

Hasan Zerze ◽

Minseok Song ◽

Yajun Ding ◽

Runfang Mao ◽

...

Keyword(s):

Self Assembly ◽

Colloidal Particles ◽

Size Dependence ◽

Fluid Phase ◽

Two Dimensions ◽

Size Dependent ◽

Colloidal Crystallization ◽

Kinetic Effects ◽

Physical Phenomena ◽

Surrounding Fluid

Nucleation and growth of crystalline phases play an important role in a variety of physical phenomena, ranging from freezing of liquids to assembly of colloidal particles. Understanding these processes in the context of colloidal crystallization is of great importance for predicting and controlling the structures produced. In many systems, crystallites that nucleate have structures differing from those expected from bulk equilibrium thermodynamic considerations, and this is often attributed to kinetic effects. In this work, we consider the self-assembly of a binary mixture of colloids in two dimensions, which exhibits a structural transformation from a non–close-packed to a close-packed lattice during crystal growth. We show that this transformation is thermodynamically driven, resulting from size dependence of the relative free energy between the two structures. We demonstrate that structural selection can be entirely thermodynamic, in contrast to previously considered effects involving growth kinetics or interaction with the surrounding fluid phase.

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Size-dependent spectral linewidth narrowing of H-bands in organic nanoparticles of pentamethine cyanine dye

Journal of Photochemistry and Photobiology A Chemistry ◽

10.1016/j.jphotochem.2013.08.013 ◽

2013 ◽

Vol 271 ◽

pp. 124-129 ◽

Cited By ~ 8

Author(s):

Hiroshi Yao ◽

Tomoki Enseki

Keyword(s):

Cyanine Dye ◽

Organic Nanoparticles ◽

Size Dependent ◽

Spectral Linewidth

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Comparison of Optical Properties of Pyrazoline Derivative Nanoparticles

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.119.39 ◽

2007 ◽

Vol 119 ◽

pp. 39-42 ◽

Cited By ~ 1

Author(s):

Hyo Sim Kang ◽

Sun Wha Oh ◽

Young Soo Kang

Keyword(s):

Optical Properties ◽

Light Scattering ◽

Dynamic Light Scattering ◽

Fluorescence Spectroscopy ◽

Phenyl Ring ◽

Organic Nanoparticles ◽

Size Dependent ◽

Reprecipitation Method ◽

Pyrazoline Derivative

We prepared various pyrazoline derivatives which possess dimethylamino-, ethoxy-, isopropyl-phenyl ring at the 5-position of pyrazoline. The nanoparticles of pyrazoline derivative ranging from tens to hundreds of nanometers by the reprecipitation method have been successfully prepared and their optical size-dependent properties have been investigated with UV-vis, fluorescence spectroscopy, DLS (Dynamic Light Scattering) and SEM. The size-dependent optical properties of pyrazoline organic nanoparticles have been observed in the order of dimethylamino- > ethoxy- > isopropyl- in electro-donating characters.

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Tight-binding Calculation of Size Dependence of the Ionisation Potentials of Mercury Clusters

Australian Journal of Physics ◽

10.1071/ph950731 ◽

1995 ◽

Vol 48 (4) ◽

pp. 731 ◽

Cited By ~ 2

Author(s):

Jijun Zhao ◽

Xiaoshuang Chen ◽

Guanghou Wang

Keyword(s):

Size Dependence ◽

Tight Binding ◽

Expansion Method ◽

Gradual Transition ◽

Total Density ◽

Ionisation Potential ◽

Orbital Theory ◽

Tight Binding Approximation ◽

Size Dependent ◽

The Moment

The gradual transition from van der Waals-like to metallic behaviour in mercury clusters is studied by a localised orbital theory based on the tight-binding approximation. The total density of states (DOS) of the Hg., clusters is obtained by means of the moment expansion method. The Fermi energy determined from the DOS is combined with the classical conducting sphere droplet (CSD) model to calculate the size-dependent ionisation potential (IP) of the cluster. The theoretical results are in good agreement with the experiments. The size dependence of the ionisation potential has an abrupt change at n = 13, indicating that the transition from insulating to metallic behaviour begins.

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Evidencing size-dependent cooperative effects on spin crossover nanoparticles following their HS→LS relaxation

Journal of Materials Chemistry C ◽

10.1039/c8tc04315a ◽

2018 ◽

Vol 6 (46) ◽

pp. 12698-12706 ◽

Cited By ~ 4

Author(s):

Teresa Delgado ◽

Cristian Enachescu ◽

Antoine Tissot ◽

Andreas Hauser ◽

Laure Guénée ◽

...

Keyword(s):

Spin State ◽

Spin Crossover ◽

Size Dependence ◽

Relaxation Mechanism ◽

Cooperative Effects ◽

Size Dependent ◽

Liesst Effect

The size dependence of the relaxation mechanism after photo-excitation through the Light-Induced Excited Spin-State Trapping (LIESST) effect of [Fe(pz)Pt(CN)4] micro- and nanoparticles is evidenced experimentally and simulated in the framework of the mechanoelastic model.

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Size-Dependent Equilibrium Shapes of Solid Pb Inclusions in Al

Microscopy and Microanalysis ◽

10.1017/s1431927600010035 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 629-630

Author(s):

U. Dahmen ◽

E. Johnson ◽

S.Q. Xiao ◽

S. Paciornik ◽

A. Johansen

Keyword(s):

Size Dependence ◽

Equilibrium Shape ◽

Alloy System ◽

Lattice Parameter ◽

Al Alloys ◽

Size Dependent ◽

Interfacial Energies ◽

Relative Extent ◽

Equilibrium Shapes ◽

Melting And Solidification

Small Pb inclusions in Al have been studied by a number of investigators because the alloy system offers the possibility of observing the processes of melting and solidification directly. Both solids are fee, and the mutual solubility of solid Pb and Al is negligible. Despite a large difference in lattice parameter, it has been found that inclusions follow a parallel-cube orientation relationship and their equilibrium shape is a cuboctahedron, bounded by ﹛111﹜ and ﹛100﹜ facets [1]. Following Herring, the relative extent of the two types of facet directly indicates a ratio of interfacial energies γl00/γ111- However, recent investigations have shown that for inclusions in the range of a few to a few tens of nanometers the equilibrium shape becomes a function of size [2].In the present work, this size dependence of the equilibrium shape has been investigated further. Al alloys with about lat.% Pb were prepared by rapid solidification or by ion implantation, and equilibrated by annealing at about 300°C.

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