Filters








51,125 Hits in 6.5 sec

Expansive Quantum Mechanical Exploration of Chemical Reaction Paths [article]

Alberto Baiardi, Stephanie A. Grimmel, Miguel Steiner, Paul L. Türtscher, Jan P. Unsleber, Thomas Weymuth, Markus Reiher
2021 arXiv   pre-print
Quantum mechanical methods have been devised for the elucidation and clarification of reaction paths of chemical processes over decades.  ...  open-ended computational campaigns that bear the option for unexpected discoveries and the systematic approach toward uncharted territory of molecular transformations and dynamics.  ...  Automated Discovery of Chemically Reasonable Elementary Reaction Steps. J. Comput. Chem. 2013, 34, 1385–1392. [14] Habershon, S.  ... 
arXiv:2112.04944v1 fatcat:kuc33sensjfozazzmnpffnwcpe

Application of computational chemistry in chemical reactivity: a review

C. W. Chidiebere, C. E. Duru, J. P. C. Mbagwu
2021 Journal of the Nigerian Society of Physical Sciences  
Molecular orbitals are vital to giving reasons several chemical reactions occur.  ...  the utilization of quantum physics approximations.  ...  Fukui noticed that an honest approximation for reactivity can be established by observing the HOMO-LUMO.  ... 
doi:10.46481/jnsps.2021.347 fatcat:f7whfogqarguhnwxews64q7wzm

SIMULATION OF REACTIVE GEOCHEMICAL TRANSPORT PROCESSES IN CONTAMINATED AQUIFERS USING SURROGATE MODELS

Hamed Koohpayehzadeh Esfahani
2015 International Journal of GEOMATE  
To overcome this computational limitation and improve the computational feasibility of large number of repeated simulations, Genetic Programming based trained surrogate models are developed to approximately  ...  Transport of contaminant species undergoing chemical reactions in groundwater aquifers is a complex physical and biochemical process.  ...  CONCLUSION The developed methodology based on GP models for approximate simulation of the chemically reactive multiple species transport process appears to result is acceptable approximate representation  ... 
doi:10.21660/2015.15.4263 fatcat:mbxlr75j4nh5zblghcuvih5t3i

Modeling diesel combustion with tabulated kinetics and different flame structure assumptions based on flamelet approach

Tommaso Lucchini, Daniel Pontoni, Gianluca D'Errico, Bart Somers
2019 International Journal of Engine Research  
Large chemical mechanisms are required for a correct description of the combustion process, especially for the prediction of pollutant emissions.  ...  Computed results confirm the impact of the turbulent–chemistry interaction on the ignition event.  ...  For this reason, the size of the chemical mechanism which can be used in practical simulations is limited both in terms of species and reactions. 18 An interesting alternative for the reduction of CPU  ... 
doi:10.1177/1468087419862945 fatcat:7jx26zpkfzdd7cjs4sk4g3akxq

Sampling reactive pathways with random walks in chemical space: Applications to molecular dissociation and catalysis

Scott Habershon
2015 Journal of Chemical Physics  
graphs, and (iii) development of a scheme for updating the chemical graphs associated with the reaction end-points.  ...  Here, we outline a computational approach to allow automated sampling of chemical reaction pathways, including sampling of di↵erent chemical species at the reaction end-points.  ...  The author is grateful for computational resources provided by the Centre for Scientific Computing at the University of Warwick, and to Professor Joel Bowman (Emory University) for providing computer code  ... 
doi:10.1063/1.4929992 pmid:26342358 fatcat:wtf74iihh5golgff5rw5xe24wu

Assessment of conservative weighting scheme in simulating chemical vapour deposition with trace species

J.-S. Wu, W.-J. Hsiao, Y.-Y. Lian, K.-C. Tseng
2003 International Journal for Numerical Methods in Fluids  
The results of a single-cell simulation using ECWS for gas-phase reaction and surface reactions show that only ECWS can produce acceptable results with reasonable computational time.  ...  A single-cell equilibrium simulation is performed for verifying both the CWS and ECWS in treating trace species.  ...  Simulation with gas-phase reaction In this simulation, we would like to know if ECWS could reproduce the correct chemical reaction rate for before its application to the modelling of practical reactive  ... 
doi:10.1002/fld.609 fatcat:g56bisi47ndezk3foj4aszziqy

Ultra-Fast Reactive Transport Simulations When Chemical Reactions Meet Machine Learning: Chemical Equilibrium [article]

Allan M. M. Leal, Dmitrii A. Kulik, Martin O. Saar
2017 arXiv   pre-print
During reactive transport modeling, the computational cost associated with chemical reaction calculations is often 10-100 times higher than that of transport calculations.  ...  We demonstrate the use of this smart chemical equilibrium method in a reactive transport modeling example and show that, even at early simulation times, the majority of all equilibrium calculations are  ...  Thus, reactive transport simulations spend most of the computation time calculating chemical reactions and not transport processes, and typically require very long compute times.  ... 
arXiv:1708.04825v1 fatcat:e77lktpqwrbhfg6oi5376sicca

Nonequilibrium Effects in a Bimolecular Chemical Reaction in a Dilute Gas

A.S. Cukrowski, S. Fritzsche, J. Popielawski
1993 Acta Physica Polonica. A  
Analytical results for the nonequifibrium effects on the rate of chemical reaction are obtained for the line-of-centers model.  ...  Perturbation solution of the Boltzmann equation for a dilute gas with a chemical reaction A + A B + B is presented.  ...  Acknowledgments This research was supported in part by a grant from the Committee for Scientific Research.  ... 
doi:10.12693/aphyspola.84.369 fatcat:fwx2gglgprgilpuhs4etftyr4u

Vapor-phase chemical equilibrium and combined chemical and vapor–liquid equilibrium for the ternary system ethylene+water+ethanol from reaction-ensemble and reactive Gibbs-ensemble molecular simulations

Y. Mauricio Muñoz-Muñoz, Jadran Vrabec, Mario Llano-Restrepo
2015 Fluid Phase Equilibria  
In this work, the reaction-ensemble Monte Carlo (RxMC) method was used to calculate the chemical equilibrium of the ternary system in the vapor phase, and the reactive Gibbs-ensemble Monte Carlo (RxGEMC  ...  Reliable combined chemical and vapor-liquid equilibrium (ChVLE) data for the ternary system ethylene + water + ethanol are required for the conceptual design of a reactive separation process to obtain  ...  The reactive Gibbs-ensemble (RxGEMC) molecular simulation predictions for the bubble-point line of the reactive phase diagram and the approximate location of the reactive critical point are in very good  ... 
doi:10.1016/j.fluid.2015.06.011 fatcat:7bpoh67jofeofeultd36j3pike

Fast computation of multi-scale combustion systems

E. Chiavazzo, P. Asinari, F. Visconti
2011 Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences  
missing variables in a reactive flow simulation with a global reaction model.  ...  To this end, reduced models of homogeneous ideal gas mixtures of methane and air are first obtained by the novel Relaxation Redistribution Method (RRM) and thereafter used for the extraction of all the  ...  The one reason is the large number of kinetic equations needed for tracking each chemical species.  ... 
doi:10.1098/rsta.2011.0026 pmid:21576153 fatcat:slop3cqiofazndgwf3sgobbgjy

Methods for exploring reaction space in molecular systems

Amanda L. Dewyer, Alonso J. Argüelles, Paul M. Zimmerman
2017 Wiley Interdisciplinary Reviews. Computational Molecular Science  
Novel methods that make hypotheses for elementary steps and complementary means for reaction path and transition state (TS) optimization are lowering the amount of chemical intuition and user effort required  ...  The area of reaction mechanism discovery simulation has taken considerable strides in recent years.  ...  A Wish-List for Reaction Discovery Simulations As progress in reaction mechanism exploration continues, we will move closer and closer to uncovering the full details of chemical reactions, with less and  ... 
doi:10.1002/wcms.1354 fatcat:gff2bco52rbjlfj3ldovisepbe

Molecular dynamics simulations of elementary chemical processes in liquid water using combined density functional and molecular mechanics potentials. II. Charge separation processes

M. Strnad, M. T. C. Martins-Costa, C. Millot, I. Tuñón, M. F. Ruiz-López, J. L. Rivail
1997 Journal of Chemical Physics  
A new approach to carry out molecular dynamics simulations of chemical reactions in solution using combined density functional theory/molecular mechanics potentials is presented.  ...  We describe here a method that consists in the simulation of short trajectories starting from an equilibrated transition state in solution, the structure of which has been approximately established.  ...  CHEMICAL REACTION SIMULATION METHOD As mentioned above, the simulation of a reactive trajectory for a process with a large activation barrier ͑more than a few kT͒ cannot be afforded with standard techniques  ... 
doi:10.1063/1.473458 fatcat:fxnqhbtwe5bjzgvz5gwcvgupuq

Stochastic atomistic simulation of polycyclic aromatic hydrocarbon growth in combustion

Jason Y. W. Lai, Paolo Elvati, Angela Violi
2014 Physical Chemistry, Chemical Physics - PCCP  
Simulations elucidated novel, atomistic insight into the chemical composition and morphology of nascent PAHs.  ...  The Stochastic Nanoparticle Simulator (SNAPS) has been developed to investigate Polycyclic Aromatic Hydrocarbon (PAH) growth in combustion.  ...  Nevertheless, the simulations are able to achieve reasonable accuracy after approximately 5 ms, which correspond to the regions of primary interest.  ... 
doi:10.1039/c4cp00112e pmid:24647536 fatcat:7ouvw2io6vgvnl5332lr5yismm

Computational methods for multiphase flow and reactive transport problems arising in subsurface contaminant remediation

Todd Arbogast, Steve Bryant, Clint Dawson, Fredrik Saaf, Chong Wang, Mary Wheeler
1996 Journal of Computational and Applied Mathematics  
of chemical species in the subsurface.  ...  A mathematical formulation and some numerical approximation techniques are described for a system of coupled partial differential and algebraic equations describing multiphase flow, transport and interactions  ...  At the Center for Subsurface Modeling at the University of Texas, we are developing parallel simulators for modeling multiphase flow and multicomponent reactive transport, and applying these simulators  ... 
doi:10.1016/0377-0427(96)00015-5 fatcat:invvxdnza5emxd5x4u4jy2ykly

Local reactivity of fullerenes and nano-device applications

Seongjun Park, Deepak Srivastava, Kyeongjae Cho
2001 Nanotechnology  
This understanding provides an insight into the use of chemically doped endo-fullerenes as suitable target material for a recently proposed design of a solid-state quantum computer.  ...  A conceptual framework to understand the chemical reactivity of fullerenes is developed as a design tool for nano-scale device applications.  ...  materials simulations'.  ... 
doi:10.1088/0957-4484/12/3/308 fatcat:hytg4bf7ifcqnns2l7hifvbbry
« Previous Showing results 1 — 15 out of 51,125 results