Potential energy construction in the diabatic picture for quantum mechanical rate constants of intermolecular proton transfer

2017 ◽  
Vol 19 (25) ◽  
pp. 16857-16866 ◽  
Author(s):  
Yuta Hori ◽  
Tomonori Ida ◽  
Motohiro Mizuno

We propose a simple method for potential construction in the diabatic picture and the estimation of thermal rate constants for intermolecular proton transfer reactions using quantum dynamics simulations carried out on the constructed potentials.

2015 ◽  
Vol 14 (02) ◽  
pp. 1550013 ◽  
Author(s):  
Feng Guo ◽  
Hong Zhang ◽  
Chao-Yang Zhang ◽  
Xin-Lu Cheng ◽  
Hai-Quan Hu

To understand the reaction mechanism involving hydrogen transfers through hydrogen-bond bridge, we carried out both Self-Consistent Charge Density Functional Tight-Binding (SCC-DFTB) calculations of bulk nitromethane and Density Functional Theory (DFT) calculations of singlet ground state/triplet excited state molecular nitromethane using B3LYP functional. Firstly, we tuned the repulsive parameters of the SCC-DFTB method for nitromethane with dataset calculated from DFT at B3LYP/6-311g level. The molecular dynamics simulations are carried out with tuned parameters to get the dynamical properties of the bulk nitromethane, and the static calculations are intended to give energy profile of the reaction process. These calculations indicate the excitation of nitromethane molecule making the proton transfer reactions possible, and lowering the reaction barrier.


1979 ◽  
Vol 57 (12) ◽  
pp. 1518-1523 ◽  
Author(s):  
Gervase I. Mackay ◽  
Scott D. Tanner ◽  
Alan C. Hopkinson ◽  
Diethard K. Bohme

Rate constants measured with the flowing afterglow technique at 298 ± 2 K are reported for the proton-transfer reactions of H3O+ with CH2O, CH3CHO, (CH3)2CO, HCOOH, CH3COOH, HCOOCH3, CH3OH, C2H5OH, (CH3)2O, and CH2CO. Dissociative proton-transfer was observed only with CH3COOH. The rate constants are compared with the predictions of various theories for ion–molecule collisions. The protonation is discussed in terms of the energetics and mechanisms of various modes of dissociation.


1982 ◽  
Vol 60 (20) ◽  
pp. 2594-2605 ◽  
Author(s):  
Gervase I. Mackay ◽  
Asit B. Rakshit ◽  
Diethard K. Bohme

Flowing afterglow measurements at 296 ± 2 K are reported which explore three aspects of the gas-phase acid–base chemistry of the methoxide anion. Firstly, the intrinsic reactivity of this ion has been determined from measurements of rate constants for solvent-free proton-transfer reactions with molecules more acidic than methanol including CH2=C=CH2, C6H5CH3, C2H5OH, C2H2, CH3CN, CH3COCH3, CH3CHO, CH3NO2, and HCN. Secondly, equilibrium constant measurements have been performed for solvent-free proton-transfer reactions which provide a gas-phase scale of acidities for these molecules relative to the acidity of methanol. Finally, rate constants were measured for the reactions of these acids with methoxide ions solvated with up to three molecules of methanol. The results establish trends in reactivity as a function of step–wise solvation when relative acidity is preserved and when a reversal occurs in the relative acidity upon solvation.


1972 ◽  
Vol 50 (1) ◽  
pp. 24-30 ◽  
Author(s):  
A. Jarczewski ◽  
K. T. Leffek

The second-order rate constants have been measured over a range of temperatures for the proton-transter reactions from di-(4-nitrophenyl)methane to ethoxide, isopropoxide, and t-butoxide ions in solvents consisting of the corresponding alcohols containing 10% toluene by volume. The activation parameters ΔH≠ and ΔS≠ have been calculated and an interpretation of them is given in terms of solvation effects during the activation process. A comparison between the activation parameters for proton transfers and E2 olefin-forming β-elimination reactions is made and discussed with respect to transition state character of the latter reactions.


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