Transferable Tight-Binding Approach Of Si-H Interactions

1997 ◽  
Vol 491 ◽  
Author(s):  
Eunja Kim ◽  
Seung Mi Lee ◽  
Young Hee Lee
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Molecular Dynamics Simulations ◽  
Energy Levels ◽  
Tight Binding ◽  
Electronic Energy ◽  
Binding Parameters ◽  
Exponential Factor ◽  
Dynamics Simulations ◽  
Electronic Energy Levels

ABSTRACTWe construct transferable tight-binding parameters of silicon-hydrogen interactions, reproducing the electronic energy levels and vibrational frequencies of the silane(SiH4) molecule accurately. The potential function was rescaled with the exponential factor in order to ensure that the potential energy is smooth at an appropriate cut-off distance, which is very important in molecular-dynamics simulations. The parameters have been applied to other molecules and various surfaces such as hydrogenated Si(100) surfaces, for example, monohydride, dihydride, and (3×1) phase.

Reduced-dimensional surface hopping with offline–online computations

2021 ◽  
Author(s):  
Zachary Morrow ◽  
Hyuk-Yong Kwon ◽  
Carl Tim Kelley ◽  
Elena Jakubikova
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Molecular Dynamics Simulations ◽  
Potential Energy Surfaces ◽  
Energy Levels ◽  
Surface Hopping ◽  
Dynamics Simulations ◽  
Energy Surfaces ◽  
Nuclear Geometry ◽  
Dimensional Surface

Molecular dynamics simulations often classically evolve the nuclear geometry on adiabatic potential energy surfaces (PESs), punctuated by random hops between energy levels in regions of strong coupling, in an algorithm...

scholarly journals Tight-Binding Molecular Dynamics Simulations on Point Defects Diffusion and Interactions in Crystalline Silicon

1995 ◽  
Vol 396 ◽  
Author(s):  
M. tang ◽  
L. colombo ◽  
T. Diaz De La Rubia
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Point Defects ◽  
Crystalline Silicon ◽  
Tight Binding ◽  
Diffusion Path ◽  
Binding Energies ◽  
Defect Clusters ◽  
Dynamics Simulations

AbstractTight-binding molecular dynamics (TBMD) simulations are performed (i) to evaluate the formation and binding energies of point defects and defect clusters, (ii) to compute the diffusivity of self-interstitial and vacancy in crystalline silicon, and (iii) to characterize the diffusion path and mechanism at the atomistic level. In addition, the interaction between individual defects and their clustering is investigated.

Mechanisms and kinetics of initial pyrolysis and combustion reactions of 1,1-diamino-2,2-dinitroethylene from density functional tight-binding molecular dynamics simulations

2019 ◽  
Vol 97 (11) ◽  
pp. 795-804 ◽  
Author(s):  
Dong Xiang ◽  
Weihua Zhu
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Density Functional ◽  
Tight Binding ◽  
Combustion Process ◽  
Exponential Factor ◽  
Three Stages ◽  
Dynamics Simulations ◽  
Combustion Processes ◽  
Kinetics Of

The density functional tight-binding molecular dynamics approach was used to study the mechanisms and kinetics of initial pyrolysis and combustion reactions of isolated and multi-molecular FOX-7. Based on the thermal cleavage of bridge bonds, the pyrolysis process of FOX-7 can be divided into three stages. However, the combustion process can be divided into five decomposition stages, which is much more complex than the pyrolysis reactions. The vibrations in the mean temperature contain nodes signifying the formation of new products and thereby the transitions between the various stages in the pyrolysis and combustion processes. Activation energy and pre-exponential factor for the pyrolysis and combustion reactions of FOX-7 were obtained from the kinetic analysis. It is found that the activation energy of its pyrolysis and combustion reactions are very low, making both take place fast. Our simulations provide the first atomic-level look at the full dynamics of the complicated pyrolysis and combustion process of FOX-7.

scholarly journals Multiscale QM/MM Molecular Dynamics Simulations of the Trimeric Major Light-Harvesting Complex II

2021 ◽  
Author(s):  
Sayan Maity ◽  
Vangelis Daskalakis ◽  
Marcus Elstner ◽  
Ulrich Kleinekathöfer
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Chlorophyll A ◽  
Density Functional ◽  
Light Harvesting ◽  
Higher Plants ◽  
Tight Binding ◽  
Spectral Densities ◽  
Light Harvesting Complex ◽  
Dynamics Simulations

Photosynthetic processes are driven by sunlight. Too little of it and the photosynthetic machinery cannot produce the reductive power to drive the anabolic pathways. Too much sunlight and the machinery can get damaged. In higher plants, the major Light Harvesting Complex (LHCII) efficiently absorbs the light energy, but can also dissipate it when in excess (quenching). In order to study the dynamics related to the quenching process but also the exciton dynamics in general, one needs to accurately determine the so-called spectral density which describes the coupling between the relevant pigment modes and the environmental degrees of freedom. To this end, Born–Oppenheimer molecular dynamics simulations in a quantum mechanics/molecular mechanics (QM/MM) fashion utilizing the density functional based tight binding (DFTB) method have been performed for the ground state dynamics. Subsequently, the time-dependent extension of the long-range-corrected DFTB scheme has been employed for the excited state calculations of the individual chlorophyll-a molecules in the LHCII complex. The analysis of this data resulted in spectral densities showing an astonishing agreement with the experimental counterpart in this rather large system. This consistency with an experimental observable also supports the accuracy, robustness, and reliability of the present multi-scale scheme. In addition, the resulting spectral densities and site energies were used to determine the exciton transfer rate within a special pigment pair consisting of a chlorophyll-a and a carotenoid molecule which is assumed to play a role in the balance between the light harvesting and quenching modes.

An Ab-Initio Multicenter Tight-Binding Model for Molecular Dynamics Simulations

1988 ◽  
Vol 141 ◽  
Author(s):  
Otto F. Sankey ◽  
David J. Niklewski
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Local Density ◽  
Tight Binding ◽  
Real Space ◽  
Hamiltonian Matrix ◽  
Binding Model ◽  
Annealing Study ◽  
Total Energies ◽  
Dynamics Simulations

AbstractA new, approximate method has been developed for computing total energies and forces for a variety of applications including molecular dynamics simulations of covalent materials. The method is tight-binding-like and is based on the local density approximation within the pseudopotential scheme. Slightly excited pseudo-atomic-orbitals are used, and the tight-binding Hamiltonian matrix is obtained in real space. The method is used to find the total energies for five crystalline phases of Si and the Si 2 molecule. Excellent agreement is found with experiment. A molecular dynamics simulated annealing study has been performed on the Si 3 molecule to determine the ground state configuration.

Tight-Binding Molecular Dynamics Study of Liquid and Amorphous Carbon

1992 ◽  
Vol 291 ◽  
Author(s):  
C. Z. Wang ◽  
K. M. Ho ◽  
C. T. Chan
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Amorphous Carbon ◽  
Simulation Study ◽  
Tight Binding ◽  
Sufficient Accuracy ◽  
Complex Carbon ◽  
Dynamics Simulations

ABSTRACTTight-binding molecular-dynamics simulations are performed to study the structure of liquid and amorphous carbon. Comparisons of our results with ab initiomolecular dynamics (Car-Parrinello) results and experimental data show that the scheme has sufficient accuracy and efficiency for realistic simulation study of the structural properties of complex carbon systems.

Melting at Mg/Al interface in Mg-Al-Mg nanolayer by molecular dynamics simulations

2021 ◽  
Author(s):  
Xue-Qi Lv ◽  
Xiong-Ying Li
Keyword(s):  
Molecular Dynamics ◽  
Heat Capacity ◽  
Distribution Function ◽  
Potential Energy ◽  
Density Distribution ◽  
Molecular Dynamics Simulations ◽  
Regional Research ◽  
Melting Temperatures ◽  
Essential Step ◽  
Dynamics Simulations

Abstract The melting at the magnesium/aluminum (Mg/Al) interface is an essential step during the fabrications of Mg-Al structural materials and biomaterials. We carried out molecular dynamics simulations on the melting at the Mg/Al interface in a Mg-Al-Mg nanolayer via analyzing the changes of average atomic potential energy, Lindemann index, heat capacity, atomic density distribution and radial distribution function with temperature. The melting temperatures (T m) of the nanolayer and the slabs near the interface are significantly sensitive to the heating rate (v h) over the range of v h≤4.0 K/ps. The distance (d) range in which the interface affects the melting of the slabs is predicted to be (-98.2, 89.9) Å at v h→0, if the interface is put at d=0 and Mg (Al) is located at the left (right) side of the interface. The (T m) of the Mg (Al) slab just near the interface (e.g., d=4.0 Å) is predicted to be 926.8 K (926.6 K) at v h→0, with 36.9 K (37.1 K) below 963.7 K for the nanolayer. These results highlight the importance of regional research on the melting at an interface in the nanolayers consisting of two different metals.

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