scholarly journals Benchmark ab Initio Energy Profiles for the Gas-Phase SN2 Reactions Y-+ CH3X → CH3Y + X-(X,Y = F,Cl,Br). Validation of Hybrid DFT Methods

2001 ◽  
Vol 105 (5) ◽  
pp. 895-904 ◽  
Author(s):  
Srinivasan Parthiban ◽  
Glênisson de Oliveira ◽  
Jan M. L. Martin
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Dft Methods ◽  
Sn2 Reactions ◽  
Energy Profiles

Gas Phase and Aqueous Thermochemistry of Hydrazine and Related Radicals and the Energy Profiles of Reactions with H•and OH•:  An ab Initio Study

1997 ◽  
Vol 101 (26) ◽  
pp. 4761-4769 ◽  
Author(s):  
D. A. Armstrong ◽  
D. Yu ◽  
A. Rauk
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Ab Initio Study ◽  
Energy Profiles

scholarly journals Gas-phase computational study of tetra-n-butylammonium ion conformational mobility

2021 ◽  
Vol 340 ◽  
pp. 01045
Author(s):  
Pavel Tyapkin ◽  
Denis Rychkov
Keyword(s):  
Phase Transitions ◽  
Gas Phase ◽  
Solid Electrolytes ◽  
Computational Study ◽  
Conformational Mobility ◽  
Dft Methods ◽  
Energy Profiles

The energy profiles of various configurations of the tetra-n-butylammonium ion (Bu4N+) arising by changing the angle between a pair of butyl ligands, as well as by rotating of various alkyl fragments in gas phase, were calculated using DFT methods. A hypothesis about the most probable way of changing the conformations of tetra-n-butylammonium ions during the phase transitions in highly conductive solid electrolytes was proposed.

Ab initio investigation of the potential energy profiles for the gas phase CH4+O2+(2Πg) reaction system

2001 ◽  
Vol 114 (14) ◽  
pp. 6119-6127 ◽  
Author(s):  
Stephan Irle ◽  
Keiji Morokuma
Keyword(s):  
Potential Energy ◽  
Ab Initio ◽  
Gas Phase ◽  
Reaction System ◽  
Energy Profiles ◽  
Potential Energy Profiles

A high-level ab initio investigation of identity and nonidentity gas-phase SN2 reactions of halide ions with halophosphines

2001 ◽  
Vol 210-211 ◽  
pp. 1-11 ◽  
Author(s):  
Theis I. Sølling ◽  
Addy Pross ◽  
Leo Radoma
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Halide Ions ◽  
Sn2 Reactions ◽  
High Level

Gas-phase measurements of the influence of stepwise solvation on the kinetics of SN2 reactions of solvated F− with CH3Cl and CH3Br and of solvated Cl− with CH3Br

1985 ◽  
Vol 63 (11) ◽  
pp. 3007-3011 ◽  
Author(s):  
Diethard K. Bohme ◽  
Asit B. Raksit
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Specific Rate ◽  
Flowing Afterglow ◽  
Phase Measurements ◽  
Sn2 Reactions ◽  
Energy Profiles ◽  
Nucleophilic Displacement ◽  
Displacement Reactions ◽  
Kinetics Of

Flowing afterglow measurements are reported which reveal the influence of stepwise solvation on the nucleophilicity of F− and Cl− in the gas phase at room temperature. The specific rates of nucleophilic displacement reactions with CH3Cl and CH3Br are followed for additions of up to three molecules of solvent for F− solvated with D2O, CH3OH, and C2H5OH and for Cl− solvated with CH3OH, C2H5OH, CH3COCH3, HCOOH, and CH3COOH. The observed precipitous response of the specific rate to solvation is attributed to intermediate features of plausible reaction energy profiles.

A Systematic DFT Study of Two Elementary Steps Involving Hydrogen Peroxide and the Hydroxyl Radical in the Fenton Reaction

2018 ◽  
Author(s):  
Danilo Carmona ◽  
David Contreras ◽  
Oscar A. Douglas-Gallardo ◽  
Stefan Vogt-Geisse ◽  
Pablo Jaque ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Ab Initio ◽  
Fenton Reaction ◽  
Basis Set ◽  
Basis Sets ◽  
Dft Methods ◽  
Elementary Steps ◽  
Oxygen Oxygen ◽  
Complete Basis Set

The Fenton reaction plays a central role in many chemical and biological processes and has various applications as e.g. water remediation. The reaction consists of the iron-catalyzed homolytic cleavage of the oxygen-oxygen bond in the hydrogen peroxide molecule and the reduction of the hydroxyl radical. Here, we study these two elementary steps with high-level ab-initio calculations at the complete basis set limit and address the performance of different DFT methods following a specific classification based on the Jacob´s ladder in combination with various Pople's basis sets. Ab-initio calculations at the complete basis set limit are in agreement to experimental reference data and identified a significant contribution of the electron correlation energy to the bond dissociation energy (BDE) of the oxygen-oxygen bond in hydrogen peroxide and the electron affinity (EA) of the hydroxyl radical. The studied DFT methods were able to reproduce the ab-initio reference values, although no functional was particularly better for both reactions. The inclusion of HF exchange in the DFT functionals lead in most cases to larger deviations, which might be related to the poor description of the two reactions by the HF method. Considering the computational cost, DFT methods provide better BDE and EA values than HF and post--HF methods with an almost MP2 or CCSD level of accuracy. However, no systematic general prediction of the error based on the employed functional could be established and no systematic improvement with increasing the size in the Pople's basis set was found, although for BDE values certain systematic basis set dependence was observed. Moreover, the quality of the hydrogen peroxide, hydroxyl radical and hydroxyl anion structures obtained from these functionals was compared to experimental reference data. In general, bond lengths were well reproduced and the error in the angles were between one and two degrees with some systematic trend with the basis sets. From our results we conclude that DFT methods present a computationally less expensive alternative to describe the two elementary steps of the Fenton reaction. However, choice of approximated functionals and basis sets must be carefully done and the provided benchmark allows a systematic validation of the electronic structure method to be employed

Ab Initio Calculations on Sequential Reactions of Nitric Oxide with Titanium Ions in the Gas Phase

2020 ◽  
Vol 124 (25) ◽  
pp. 5194-5203
Author(s):  
Zahra Safaei ◽  
Alireza Shayesteh
Keyword(s):  
Nitric Oxide ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Gas Phase ◽  
Sequential Reactions

Ab initio prediction of gas phase molecular structure of 1-chlorsilatrane

1995 ◽  
Author(s):  
Gábor I. Csonka ◽  
Pál Hencsei
Keyword(s):  
Molecular Structure ◽  
Ab Initio ◽  
Gas Phase ◽  
Ab Initio Prediction

Ab Initio Study of the Carbon-to-Carbon Identity Proton Transfer from Ketene to Its Anion in the Gas Phase

2001 ◽  
Vol 123 (10) ◽  
pp. 2430-2431 ◽  
Author(s):  
Claude F. Bernasconi ◽  
Philip J. Wenzel
Keyword(s):  
Proton Transfer ◽  
Ab Initio ◽  
Gas Phase ◽  
Ab Initio Study
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