scholarly journals Numerical calculation of free-energy barriers for entangled polymer nucleation

2020 ◽  
Vol 152 (22) ◽  
pp. 224904
Author(s):  
Xiaoliang Tang ◽  
Fucheng Tian ◽  
Tingyu Xu ◽  
Liangbin Li ◽  
Aleks Reinhardt
Keyword(s):  
Free Energy ◽  
Numerical Calculation ◽  
Energy Barriers ◽  
Entangled Polymer

Calculation of the free energy barriers in the oligomerisation of Ab

10.2741/3104 ◽  
2008 ◽  
Vol Volume (13) ◽  
pp. 5614 ◽  
Author(s):  
Mookyung Cheon
Keyword(s):  
Free Energy ◽  
Energy Barriers

Microscopic mechanisms of initial oxidation of Si(100): Reaction pathways and free-energy barriers

2012 ◽  
Vol 85 (20) ◽  
Author(s):  
Kenichi Koizumi ◽  
Mauro Boero ◽  
Yasuteru Shigeta ◽  
Atsushi Oshiyama
Keyword(s):  
Free Energy ◽  
Reaction Pathways ◽  
Energy Barriers ◽  
Initial Oxidation

Nucleation free-energy barriers with Hybrid Monte-Carlo/Umbrella Sampling

2014 ◽  
Vol 16 (45) ◽  
pp. 24913-24919 ◽  
Author(s):  
M. A. Gonzalez ◽  
E. Sanz ◽  
C. McBride ◽  
J. L. F. Abascal ◽  
C. Vega ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Free Energy ◽  
Umbrella Sampling ◽  
Energy Barriers ◽  
Hybrid Monte Carlo

Nucleus-size pinning for determination of nucleation free-energy barriers and nucleus geometry

2018 ◽  
Vol 148 (18) ◽  
pp. 184104 ◽  
Author(s):  
Abhishek K. Sharma ◽  
Fernando A. Escobedo
Keyword(s):  
Free Energy ◽  
Nucleus Size ◽  
Energy Barriers

Ab initio mechanism revealing for tricalcium silicate dissolution

2021 ◽  
Author(s):  
Yunjian Li ◽  
Hui Pan ◽  
Xing Ming ◽  
Zongjin Li
Keyword(s):  
Free Energy ◽  
Ab Initio ◽  
Calcium Ions ◽  
Tricalcium Silicate ◽  
Proton Exchange ◽  
Reaction Pathways ◽  
Ab Initio Molecular Dynamics ◽  
Energy Barriers ◽  
Silicate Dissolution ◽  
Quantitative Analyses

Abstract Dissolution of mineral in water is ubiquitous in nature and industry, especially for the calcium silicate species. However, the behavior of such a complex chemical reaction is still unclear at atomic level. Here, we show that the ab initio molecular dynamics and metadynamics simulations enable quantitative analyses of reaction pathways, and the thermodynamics and kinetics of calcium ion dissolution from the tricalcium silicate (Ca3SiO5) surface. The calcium sites with different coordination environment leads to different reaction pathways and free energy barriers. The low free energy barriers lead to that the detachment of calcium ions is a ligand exchange and auto-catalytic process. Moreover, the water adsorption, proton exchange and diffusion of water into the surface layer accelerate the leaching of calcium ions from the surface step by step. The discovery in this work thus would be a landmark for revealing the mechanism of cement hydration.

Free-Energy Barriers in Spin Glasses from Multi-Overlap Simulations1

2002 ◽  
Vol 2 (1-2) ◽  
pp. 125-134
Author(s):  
Wolfhard Janke ◽  
Bernd A. Berg ◽  
Alain Billoire
Keyword(s):  
Free Energy ◽  
Spin Glasses ◽  
Energy Barriers

scholarly journals DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4509
Author(s):  
Hong-jie Qu ◽  
Lang Yuan ◽  
Cai-xin Jia ◽  
Hai-tao Yu ◽  
Hui Xu
Keyword(s):  
Free Energy ◽  
Hydrogen Atom ◽  
Gibbs Free Energy ◽  
Density Functional ◽  
Vibrational Energy ◽  
Hydrogen Atom Abstraction ◽  
Reaction Energy ◽  
Energy Barriers ◽  
Energy Correction ◽  
Kinetic Barriers

Understanding the hydrogen atom abstraction (HAA) reactions of N-heterocyclic carbene (NHC)-boranes is essential for extending the practical applications of boron chemistry. In this study, density functional theory (DFT) computations were performed for the HAA reactions of a series of NHC-boranes attacked by •CH2CN, Me• and Et• radicals. Using the computed data, we investigated the correlations of the activation and free energy barriers with their components, including the intrinsic barrier, the thermal contribution of the thermodynamic reaction energy to the kinetic barriers, the activation Gibbs free energy correction and the activation zero-point vibrational energy correction. Furthermore, to describe the dependence of the activation and free energy barriers on the thermodynamic reaction energy or reaction Gibbs free energy, we used a three-variable linear model, which was demonstrated to be more precise than the two-variable Evans–Polanyi linear free energy model and more succinct than the three-variable Marcus-theory-based nonlinear HAA model. The present work provides not only a more thorough understanding of the compositions of the barriers to the HAA reactions of NHC-boranes and the HAA reactivities of the substrates but also fresh insights into the suitability of various models for describing the relationships between the kinetic and thermodynamic physical quantities.

Sign in / Sign up

Export Citation Format

Share Document