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

1995 ◽  
Vol 48 (4) ◽  
pp. 731 ◽  
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.

SIZE-DEPENDENT EFFECTS IN ATOMIC CLUSTERS

2020 ◽  
Author(s):  
A. S. Sharipov ◽  
◽  
B. I. Loukhovitski ◽  
Keyword(s):  
Binding Energy ◽  
Physical Properties ◽  
Size Dependence ◽  
Atomic Clusters ◽  
Energy Collision ◽  
Size Dependent

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

Electrical Transport Properties of Carbon Nanotube Metal-Semiconductor Heterojunction

2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660009 ◽  
Author(s):  
Keka Talukdar ◽  
Anil Shantappa
Keyword(s):  
Electrical Transport ◽  
Nearest Neighbor ◽  
Electronic Devices ◽  
Tight Binding ◽  
Transmission Function ◽  
Topological Defects ◽  
Dynamics Simulation ◽  
Internal Stresses ◽  
Electrical Transport Properties ◽  
Tight Binding Approximation

Carbon nanotubes (CNTs) have been proved to have promising applicability in various fields of science and technology. Their fascinating mechanical, electrical, thermal, optical properties have caught the attention of today’s world. We have discussed here the great possibility of using CNTs in electronic devices. CNTs can be both metallic and semiconducting depending on their chirality. When two CNTs of different chirality are joined together via topological defects, they may acquire rectifying diode property. We have joined two tubes of different chiralities through circumferential Stone–Wales defects and calculated their density of states by nearest neighbor tight binding approximation. Transmission function is also calculated to analyze whether the junctions can be used as electronic devices. Different heterojunctions are modeled and analyzed in this study. Internal stresses in the heterojunctions are also calculated by molecular dynamics simulation.

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

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.

Luminescent Amorphous Silicon Layers

1997 ◽  
Vol 486 ◽  
Author(s):  
G. Allan ◽  
C. Delerue ◽  
M. Lannoo
Keyword(s):  
Electronic Structure ◽  
Amorphous Silicon ◽  
Radiative Recombination ◽  
Crystalline Silicon ◽  
Tight Binding ◽  
Blue Shift ◽  
Localized States ◽  
Structure Model ◽  
Radiative Recombination Rate ◽  
Tight Binding Approximation

AbstractThe electronic structure of amorphous silicon layers has been calculated within the empirical tight binding approximation using the Wooten-Winer-Weaire atomic structure model. We predict an important blue shift due to the confinement for layer thickness below 3 nm and we compare with crystalline silicon layers. The radiative recombination rate is enhanced by the disorder and the confinement but remains quite small. The comparison of our results with experimental results shows that the density of defects and localized states in the studied samples must be quite small.

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

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>

Sign in / Sign up

Export Citation Format

Share Document