نتایج جستجو برای: proton transfer

تعداد نتایج: 349521  

Journal: :physical chemistry research 0
bilal achouri laboratoire de physico chimie théorique et chimie informatique. usthb yamina belmiloud laboratoire de physico chimie théorique et chimie informatique. usthb meziane brahimi department of chemistry u.s.t.h.b. algeria

proton transfer (pt) and methyl group transfer (mgt) occurring in small biomimetic systems, formamide-formamidic acid (fa-fi), and n-formyl-n-methylformamide-(e)-methyl n-formylformimidate (nmfa-nmfi) are investigated in the gas phase and in single-walled carbon nanotubes by using the density functional theory and the oniom approach. it is shown that pt reaction is disfavoured in single-walled ...

Journal: :journal of physical & theoretical chemistry 2015
jumber kereselidze marine kvaraia george mikuchadze

the stacking mechanism of the 1h-4h proton transfer in 4-pyridone, 4-pyridinthione and p-aminopyridineare constructed. for quantitative description of this process by means of the quamtumchemicalmethod density functional theory (dft) the activation energy (

ژورنال: مواد پرانرژی 2018

The effect of the presence of compounds such as H2O, NH3, UDMH and NH2-NH2 has been reported on the inter-molecular proton transfer of 3-Nitro-1,2,4-triazole (NTO) using quantum computing. Gaussian 09 program package has been used to calculate geometry optimization and all reactions with 6-311++G(d,p) basis set. In these studies, the substances mentioned in the molecular reactions act as a cata...

The stacking mechanism of the 1H-4H proton transfer in 4-pyridone, 4-pyridinthione and p-aminopyridineare constructed. For quantitative description of this process by means of the quamtumchemicalmethod density functional theory (DFT) the activation energy (

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2008
mehdi seddiq hassan khaleghi masaud mirzaei

output characteristics of fuel cells are affected by a large number of parameters such as geometry, dimensions, construction materials and conditions of supplying fluids. in this paper a mathematical model followed by a two-dimensional numerical approach has been presented to study the fuel cell parametrically. effect of oxygen concentration at gas diffusion layer entrance, temperature and pres...

امیری, سعیده, فتحی, رضا,

In the present work, the scattering differential cross section has been investigated for ion-multi electron atoms collision in the charge transfer channel. For this purpose, an active electron model was implemented and the collision process was considered as a three-body impact in the high energy range. A semi-classical formalism was used with the eikonal distorted wave function to describe the...

Journal: :Biochemistry 2002
M L Paddock P Adelroth G Feher M Y Okamura J T Beatty

The bacterial reaction center (RC) converts light into chemical energy through the reduction of an internal quinone molecule Q(B) to Q(B)H(2). In the native RC, proton transfer is coupled to electron transfer and is not rate-controlling. Consequently, proton transfer is not directly observable, and its rate was unknown. In this work, we present a method for making proton transfer rate-controlli...

Journal: :Nature chemistry 2012
Amir Golan Ksenia B Bravaya Romas Kudirka Oleg Kostko Stephen R Leone Anna I Krylov Musahid Ahmed

Proton transfer is ubiquitous in chemistry and biology, occurring, for example, in proteins, enzyme reactions and across proton channels and pumps. However, it has always been described in the context of hydrogen-bonding networks ('proton wires') acting as proton conduits. Here, we report efficient intramolecular ionization-induced proton transfer across a 1,3-dimethyluracil dimer, a model π-st...

2007
David Lilley Fritz Eckstein Philip C. Bevilacqua

This chapter provides an overview of recent progress in understanding proton transfer in RNA enzymes. It was over 10 years ago that the previous book by the same editors was published. In that volume, there was no chapter on proton transfer. Indeed, it was unclear whether proton transfer made important contributions to RNA catalysis. Many things have changed in the last decade. Most importantly...

Journal: :Journal of the American Chemical Society 2014
Yuhua Zhou Jing Yang Haibin Su Jie Zeng San Ping Jiang William A Goddard

We have developed for fuel cells a novel proton exchange membrane (PEM) using inorganic phosphotungstic acid (HPW) as proton carrier and mesoporous silica as matrix (HPW-meso-silica) . The proton conductivity measured by electrochemical impedance spectroscopy is 0.11 S cm(-1) at 90 °C and 100% relative humidity (RH) with a low activation energy of ∼14 kJ mol(-1). In order to determine the energ...

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