Force inSCF Theories. First and second derivatives of the potential energy hypersurface of chemical reaction systems

1983 ◽  
Vol 23 (2) ◽  
pp. 387-397 ◽  
Author(s):  
H. Nakatsuji ◽  
M. Hada ◽  
K. Kanda ◽  
T. Yonezawa
Keyword(s):  
Potential Energy ◽  
Chemical Reaction ◽  
Reaction Systems ◽  
Chemical Reaction Systems ◽  
Second Derivatives ◽  
Derivatives Of ◽  
Energy Hypersurface ◽  
Potential Energy Hypersurface

A theoretical approach to the acid-catalyzed hydration of the carbonyl group: the case of formaldehyde

1991 ◽  
Vol 69 (9) ◽  
pp. 1376-1387 ◽  
Author(s):  
Daniel Peeters ◽  
Georges Leroy
Keyword(s):  
Reaction Mechanism ◽  
Potential Energy ◽  
Water Molecules ◽  
Hydration Reaction ◽  
Second Derivatives ◽  
Hydrated Proton ◽  
Energy Reaction ◽  
Derivatives Of ◽  
Energy Hypersurface ◽  
Potential Energy Hypersurface

The analysis of the hydration of formaldehyde in the presence of a hydrated proton was performed. Molecular quantum chemistry methods were used to explore the potential energy hypersurface. Calculations were performed at RHF-4-31G level. The structures were obtained through the use of first and second derivatives of the potential energy hypersurface thereby guaranteeing the nature of the extremum. The incidence of one or two water molecules on the reaction is discussed. It has been found that a low energy reaction path exists when the hydration process is catalyzed by a proton and two water molecules. The reaction mechanism rests on successive addition/elimination processes and reveals the respective roles of the oxygen lone pairs and of the C=O double bond upon the mechanism. Key words: ab initio calculations, carbonyl reactivity, acid catalysis, hydration, reaction mechanism.

Fitting Potential Energy Hypersurfaces

2012 ◽  
Author(s):  
Lionel Raff ◽  
Ranga Komanduri ◽  
Martin Hagan ◽  
Satish Bukkapatnam
Keyword(s):  
Potential Energy ◽  
Chemical Reaction ◽  
Matrix Theory ◽  
Chemical Vapor ◽  
Computational Time ◽  
Close Coupling ◽  
Chemical Reaction Mechanisms ◽  
Time Required ◽  
Energy Hypersurface ◽  
Potential Energy Hypersurface

Molecular dynamics (MD) and Monte Carlo (MC) simulations are the two most powerful methods for the investigation of dynamic behavior of atomic and molecular motions of complex systems. To date, such studies have been used to investigate chemical reaction mechanisms, energy transfer pathways, reaction rates, and product yields in a wide array of polyatomic systems. In addition, MD/MC methods have been successfully applied for the investigation of gas-surface reactions, diffusion on surfaces and in the bulk, membrane transport, and synthesis of diamond using chemical vapor deposition (CVD) techniques. The structure of vapor deposited rare gas matrices has been studied using trajectories procedures. If the chemical reaction of interest contains three atoms or fewer, various types of quantum and semiclassical calculations can be brought to bear on the problem. These methods include wave packet studies, close-coupling calculations at various levels of accuracy, and S-matrix theory. Several excellent review articles have been published describing the principal techniques and problems involved in conducting MD studies; the reader may wish to consult these as background material for this discussion. With the advent of relatively inexpensive, powerful personal computers, MD/MC simulations have become routine. Once the potential-energy hypersurface for the system has been obtained, the computations are straightforward, though time-consuming. In the majority of cases, the computational time required is on the order of hours to a few days. However, the accuracy of these simulations depends critically on the accuracy of the potential hypersurface used. The major problem associated with MD/MC investigations is the development of a potential-energy hypersurface whose topographical features are sufficiently close to those of the true, but unknown, surface that the results of the calculations are experimentally meaningful. Once the potential surface is chosen or computed, all the results from any quantum mechanical, semiclassical, or classical scattering or equilibrium calculation are determined. The only purpose of the MD calculations is to ascertain what these results are. Therefore, the most critical part of any MD/MC study is the development of the potential-energy hypersurface and the associated force field.

scholarly journals Variant and invariant states for chemical reaction systems

2015 ◽  
Vol 73 ◽  
pp. 23-33 ◽  
Author(s):  
D. Rodrigues ◽  
S. Srinivasan ◽  
J. Billeter ◽  
D. Bonvin
Keyword(s):  
Chemical Reaction ◽  
Reaction Systems ◽  
Chemical Reaction Systems ◽  
Invariant States

On decoupling rate processes in chemical reaction systems – Methods and applications

2018 ◽  
Vol 114 ◽  
pp. 296-305 ◽  
Author(s):  
Julien Billeter ◽  
Diogo Rodrigues ◽  
Sriniketh Srinivasan ◽  
Michael Amrhein ◽  
Dominique Bonvin
Keyword(s):  
Chemical Reaction ◽  
Reaction Systems ◽  
Chemical Reaction Systems ◽  
Rate Processes
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