scholarly journals Communication: Influence of external static and alternating electric fields on water from long-time non-equilibrium ab initio molecular dynamics

2017 ◽  
Vol 147 (3) ◽  
pp. 031102 ◽  
Author(s):  
Zdenek Futera ◽  
Niall J. English
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Electric Fields ◽  
Ab Initio Molecular Dynamics ◽  
Alternating Electric Fields ◽  
Long Time ◽  
Non Equilibrium

scholarly journals Possibility of realizing superionic ice VII in external electric fields of planetary bodies

2020 ◽  
Vol 6 (21) ◽  
pp. eaaz2915 ◽  
Author(s):  
Zdenek Futera ◽  
John S. Tse ◽  
Niall J. English
Keyword(s):  
Molecular Dynamics ◽  
Electric Field ◽  
Ab Initio ◽  
Electric Fields ◽  
State Of The Art ◽  
Ab Initio Molecular Dynamics ◽  
Theoretical Studies ◽  
Potential Candidate ◽  
External Electric Fields ◽  
Ice Phase

In a superionic (SI) ice phase, oxygen atoms remain crystallographically ordered while protons become fully diffusive as a result of intramolecular dissociation. Ice VII’s importance as a potential candidate for a SI ice phase has been conjectured from anomalous proton diffusivity data. Theoretical studies indicate possible SI prevalence in large-planet mantles (e.g., Uranus and Neptune) and exoplanets. Here, we realize sustainable SI behavior in ice VII by means of externally applied electric fields, using state-of-the-art nonequilibrium ab initio molecular dynamics to witness at first hand the protons’ fluid dance through a dipole-ordered ice VII lattice. We point out the possibility of SI ice VII on Venus, in its strong permanent electric field.

scholarly journals Ab Initio Molecular Dynamics Study of Methanol-Water Mixtures under External Electric Fields

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3371 ◽  
Author(s):  
Giuseppe Cassone ◽  
Adriano Sofia ◽  
Jiri Sponer ◽  
A. Marco Saitta ◽  
Franz Saija
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Electric Fields ◽  
Structural Changes ◽  
Chemical Reactivity ◽  
Pure Water ◽  
Ab Initio Molecular Dynamics ◽  
Sudden Increase ◽  
Molar Ratios ◽  
Dynamics Simulations

Intense electric fields applied on H-bonded systems are able to induce molecular dissociations, proton transfers, and complex chemical reactions. Nevertheless, the effects induced in heterogeneous molecular systems such as methanol-water mixtures are still elusive. Here we report on a series of state-of-the-art ab initio molecular dynamics simulations of liquid methanol-water mixtures at different molar ratios exposed to static electric fields. If, on the one hand, the presence of water increases the proton conductivity of methanol-water mixtures, on the other, it hinders the typical enhancement of the chemical reactivity induced by electric fields. In particular, a sudden increase of the protonic conductivity is recorded when the amount of water exceeds that of methanol in the mixtures, suggesting that important structural changes of the H-bond network occur. By contrast, the field-induced multifaceted chemistry leading to the synthesis of e.g., hydrogen, dimethyl ether, formaldehyde, and methane observed in neat methanol, in 75:25, and equimolar methanol-water mixtures, completely disappears in samples containing an excess of water and in pure water. The presence of water strongly inhibits the chemical reactivity of methanol.

ACTION-DERIVED AB INITIO MOLECULAR DYNAMICS

2009 ◽  
Vol 01 (03) ◽  
pp. 469-482 ◽  
Author(s):  
S. JUN ◽  
S. PENDURTI ◽  
I.-H. LEE ◽  
S. Y. KIM ◽  
H. S. PARK ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Energy Surface ◽  
Atomic System ◽  
Minimum Energy ◽  
Md Simulations ◽  
Ab Initio Molecular Dynamics ◽  
Least Action Principle ◽  
Least Action ◽  
Long Time

Action-derived molecular dynamics (ADMD) is a numerical method to search for minimum-energy dynamic pathways on the potential-energy surface of an atomic system. The method is based on Hamilton's least-action principle and has been developed for problems of activated processes, rare events, and long-time simulations. In this paper, ADMD is further extended to incorporate ab initio total-energy calculations, which enables the detailed electronic analysis of transition states as well as the exploration of energy landscapes. Three numerical examples are solved to demonstrate the capability of this action-derived ab initio molecular dynamics (MD). The proposed approach is expected to circumvent the severe time-scale limitation of conventional ab intio MD simulations.

scholarly journals Vibrational energy relaxation of interfacial OH on a water-covered α-Al2O3(0001) surface: a non-equilibrium ab initio molecular dynamics study

2021 ◽  
Author(s):  
Giacomo Melani ◽  
Yuki Nagata ◽  
Peter Saalfrank
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
In Silico ◽  
Vibrational Energy ◽  
Ab Initio Molecular Dynamics ◽  
Vibrational Energy Relaxation ◽  
Vibrational Dynamics ◽  
Time Resolved ◽  
Α Al2o3 ◽  
Non Equilibrium

Vibrational dynamics and relaxation of excited non-hydrogen bonded OH-aluminols from non-equilibrium AIMD, towards in silico time-resolved VSF experiments.

scholarly journals Solid electrolyte interphase formation between the Li0.29La0.57TiO3 solid-state electrolyte and a Li-metal anode: an ab initio molecular dynamics study

RSC Advances ◽  
2020 ◽  
Vol 10 (15) ◽  
pp. 9000-9015 ◽  
Author(s):  
Diego E. Galvez-Aranda ◽  
Jorge M. Seminario
Keyword(s):  
Molecular Dynamics ◽  
Solid State ◽  
Ab Initio ◽  
Electric Fields ◽  
Solid Electrolyte Interphase ◽  
Ab Initio Molecular Dynamics ◽  
Solid State Electrolyte ◽  
Metal Anode ◽  
Electrochemical Interface ◽  
Formation And Evolution

An ab initio molecular dynamics study of an electrochemical interface between a solid-state-electrolyte Li0.29La0.57TiO3 and Li-metal to analyze interphase formation and evolution when external electric fields are applied.

scholarly journals Ab initio Molecular Dynamics Simulations of Field-Coupled Nanocomputing Molecules

2021 ◽  
Vol 16 (1) ◽  
pp. 1-8
Author(s):  
Yuri Ardesi ◽  
Alessandro Gaeta ◽  
Giuliana Beretta ◽  
Gianluca Piccinini ◽  
Mariagrazia Graziano
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Charge Distribution ◽  
Electric Fields ◽  
Reducing Power ◽  
Ab Initio Molecular Dynamics ◽  
Molecular Vibrations ◽  
Realistic Situation ◽  
Dynamics Simulations ◽  
The Impact

Molecular Field-Coupled Nanocomputing (FCN) represents one of the most promising solutions to overcome the issues introduced by CMOS scaling. It encodes the information in the molecule charge distribution and propagates it through electrostatic intermolecular interaction. The need for charge transport is overcome, hugely reducing power dissipation.At the current state-of-the-art, the analysis of molecular FCN is mostly based on quantum mechanics techniques, or ab initio evaluated transcharacteristics. In all the cases, studies mainly consider the position of charges/atoms to be fixed. In a realistic situation, the position of atoms, thus the geometry, is subjected to molecular vibrations. In this work, we analyse the impact of molecular vibrations on the charge distribution of the 1,4-diallyl butane. We employ Ab Initio Molecular Dynamics to provide qualitative and quantitative results which describe the effects of temperature and electric fields on molecule charge distribution, taking into account the effects of molecular vibrations. The molecules are studied at near-absolute zero, cryogenic and ambient temperature conditions, showing promising results which proceed towards the assessment of the molecular FCN technology as a possible candidate for future low-power digital electronics. From a modelling perspective, the diallyl butane demonstrates good robustness against molecular vibrations, further confirming the possibility to use static transcharacteristics to analyse molecular circuits.

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.

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