Electronic state dependence of the ion–molecule reaction CH3CN+ + CH3CN → CH4CN+ + CH2CN: threshold electron–secondary ion coincidence (TESICO) and direct ab initio molecular dynamics study

2010 ◽  
Vol 12 (47) ◽  
pp. 15399 ◽  
Author(s):  
Hiroto Tachikawa ◽  
Takahiro Fukuzumi ◽  
Kazushige Inaoka ◽  
Inosuke Koyano
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Electronic State ◽  
State Dependence ◽  
Ab Initio Molecular Dynamics ◽  
Molecule Reaction ◽  
Secondary Ion

Control of the adiabatic electronic state in ab initio molecular dynamics

1993 ◽  
Vol 98 (8) ◽  
pp. 6361-6368 ◽  
Author(s):  
Ettore S. Fois ◽  
James I. Penman ◽  
Paul A. Madden
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Electronic State ◽  
Ab Initio Molecular Dynamics

Dissociation mechanism from highly charged bromophenol: ab initio molecular dynamics simulations

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Satoshi Ohmura ◽  
Kiyonobu Nagaya ◽  
Fuyuki Shimojo ◽  
Makoto Yao
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Electronic State ◽  
Density Functional ◽  
Ab Initio Molecular Dynamics ◽  
Electronic Temperature ◽  
Multi Stage ◽  
Dissociation Mechanisms ◽  
Dynamics Simulations

AbstractDissociation mechanisms are studied by ab initio molecular dynamics simulations based on density functional theory for the highly charged bromophenol (C6H4OHBr)n+ (n ≤ 10) in the ground electronic state and in an electronic state which has a high electronic temperature Te characterized by Fermi–Dirac distribution. In the case of the ground state, the dissociation occurs through a sequential multi-stage process. At times shorter than 20 fs after the molecule is charged, hydrogens are dissociated from the molecule and, subsequently, the carbon ring breaks at about 150 fs In the case of an electronic state with high Te, the mechanism changes from a sequential dissociation process to a simultaneous process occurring at Te > 5 eV. To estimate the charge transfer time in a molecular bromide parent ion with +6 charge, which is generated through Auger cascades, we also performed nonadiabatic quantum-mechanical molecular dynamics (NAQMD) simulations that include the effects of nonadiabatic electronic transition with a surface-hopping approach.

scholarly journals Ab Initio Molecular Dynamics Simulation Study on the Stereo Reactions between Atomic Oxygen Anion and Methane

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2495 ◽  
Author(s):  
Weihua Wang ◽  
Wenling Feng ◽  
Wenliang Wang ◽  
Ping Li
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Atomic Oxygen ◽  
Exothermic Reaction ◽  
Dynamics Simulation ◽  
Negative Ion ◽  
Ab Initio Molecular Dynamics ◽  
Oxygen Anion ◽  
Major Pathway ◽  
Molecule Reaction

Ion–molecule reaction between atomic oxygen anion (O−) and methane (CH4) has been systematically investigated employing the on-the-fly ab initio molecular dynamics simulations. Besides the major H-abstraction process as the exothermic reaction studied widely, an endothermic pathway to produce OCH3− and H is also observed in this study. Three typical O− attack modes with reference to the pyramid structure of CH4 fixed in space have been considered. It was found that the internal motions of the radical products are significantly dependent on the O− attack modes. As for the reaction between O− and the thermally vibrating CH4, the major pathway to produce OH− and CH3 is preferred by the direct H-abstraction and the minor pathway to produce H and OCH3− is the roaming reaction via the transient negative ion [HO-CH3]−.

Combustion Driven by Fragment-based Ab Initio Molecular Dynamics Simulation

2019 ◽  
Author(s):  
Liqun Cao ◽  
Jinzhe Zeng ◽  
Mingyuan Xu ◽  
Chih-Hao Chin ◽  
Tong Zhu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Large Scale ◽  
Methane Combustion ◽  
Combustion Method ◽  
Dynamics Simulation ◽  
Ab Initio Molecular Dynamics ◽  
Computational Time ◽  
Combustion Mechanism ◽  
Daily Lives

Combustion is a kind of important reaction that affects people's daily lives and the development of aerospace. Exploring the reaction mechanism contributes to the understanding of combustion and the more efficient use of fuels. Ab initio quantum mechanical (QM) calculation is precise but limited by its computational time for large-scale systems. In order to carry out reactive molecular dynamics (MD) simulation for combustion accurately and quickly, we develop the MFCC-combustion method in this study, which calculates the interaction between atoms using QM method at the level of MN15/6-31G(d). Each molecule in systems is treated as a fragment, and when the distance between any two atoms in different molecules is greater than 3.5 Å, a new fragment involved two molecules is produced in order to consider the two-body interaction. The deviations of MFCC-combustion from full system calculations are within a few kcal/mol, and the result clearly shows that the calculated energies of the different systems using MFCC-combustion are close to converging after the distance thresholds are larger than 3.5 Å for the two-body QM interactions. The methane combustion was studied with the MFCC-combustion method to explore the combustion mechanism of the methane-oxygen system.

scholarly journals A Review on Combination of Ab Initio Molecular Dynamics and NMR Parameters Calculations

2021 ◽  
Vol 22 (9) ◽  
pp. 4378
Author(s):  
Anna Helena Mazurek ◽  
Łukasz Szeleszczuk ◽  
Dariusz Maciej Pisklak
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Small Amplitude ◽  
Ab Initio Molecular Dynamics ◽  
Quantum Mechanical ◽  
Time Step ◽  
Noticeable Effect ◽  
Nmr Parameters ◽  
Mechanical Methods ◽  
Simulation Time

This review focuses on a combination of ab initio molecular dynamics (aiMD) and NMR parameters calculations using quantum mechanical methods. The advantages of such an approach in comparison to the commonly applied computations for the structures optimized at 0 K are presented. This article was designed as a convenient overview of the applied parameters such as the aiMD type, DFT functional, time step, or total simulation time, as well as examples of previously studied systems. From the analysis of the published works describing the applications of such combinations, it was concluded that including fast, small-amplitude motions through aiMD has a noticeable effect on the accuracy of NMR parameters calculations.

scholarly journals Temperature-Dependent Properties of Molten Li2BeF4 Salt Using Ab Initio Molecular Dynamics

ACS Omega ◽  
2021 ◽  
Author(s):  
Khagendra Baral ◽  
Saro San ◽  
Ridwan Sakidja ◽  
Adrien Couet ◽  
Kumar Sridharan ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Ab Initio Molecular Dynamics ◽  
Temperature Dependent ◽  
Temperature Dependent Properties
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