Molecular Dynamics Simulation Applied to the Study of Optical Absorption Spectra of Nd2O3

1991 ◽  
Vol 02 (01) ◽  
pp. 348-352
Author(s):  
SVERKER EDVARDSSON ◽  
MATS WOLF ◽  
JOSH THOMAS ◽  
ANTONIO FLORES
Keyword(s):  
Molecular Dynamics ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Md Simulation ◽  
Rare Earth Ions ◽  
Dynamics Simulation ◽  
Quantum Mechanical ◽  
Optical Absorption Spectra ◽  
Mechanical Formalism ◽  
Quantum Mechanical Formalism

An analysis is made of the optical absorption spectra for rare-earth ions in the presence of different local crystal environments. A molecular dynamics (MD) simulation is performed to provide a large ensemble of configurations for which the quantum-mechanical formalism of Judd and Ofelt for electric dipole transitions has been applied. Preliminary calculations for Nd2O3 are presented from which a dynamical picture of the spectrum emerges in which the intensity of some lines are seen to undergo substantial changes during the simulation. This suggests the existence of special arrangements of atoms for which transitions are particularly favorable.

Hydration of iron–porphyrins: ab initio quantum mechanical charge field molecular dynamics simulation study

2017 ◽  
Vol 19 (45) ◽  
pp. 30822-30833 ◽  
Author(s):  
Syed Tarique Moin ◽  
Thomas S. Hofer
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Ab Initio ◽  
Md Simulation ◽  
Dynamics Simulation ◽  
Quantum Mechanical ◽  
Simulation Approach ◽  
Iron Porphyrins ◽  
Charge Field ◽  
Mechanical Charge

The ab initio quantum mechanical charge field molecular dynamics (QMCF-MD) simulation approach was successfully applied to Fe2+–P and Fe3+–P in water to evaluate their structural, dynamical and energetic properties.

scholarly journals Molecular dynamics simulation of sI methane hydrate under compression and tension

2020 ◽  
Vol 18 (1) ◽  
pp. 69-76
Author(s):  
Qiang Wang ◽  
Qizhong Tang ◽  
Sen Tian
Keyword(s):  
Molecular Dynamics ◽  
Methane Hydrate ◽  
Fracture Process ◽  
Md Simulation ◽  
Maximum Stress ◽  
Dynamics Simulation ◽  
Tensile Fracture ◽  
Maximum Compressive Stress ◽  
Motion State ◽  
Stress States

AbstractMolecular dynamics (MD) analysis of methane hydrate is important for the application of methane hydrate technology. This study investigated the microstructure changes of sI methane hydrate and the laws of stress–strain evolution under the condition of compression and tension by using MD simulation. This study further explored the mechanical property and stability of sI methane hydrate under different stress states. Results showed that tensile and compressive failures produced an obvious size effect under a certain condition. At low temperature and high pressure, most of the clathrate hydrate maintained a stable structure in the tensile fracture process, during which only a small amount of unstable methane broke the structure, thereby, presenting a free-motion state. The methane hydrate cracked when the system reached the maximum stress in the loading process, in which the maximum compressive stress is larger than the tensile stress under the same experimental condition. This study provides a basis for understanding the microscopic stress characteristics of methane hydrate.

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