Theoretical investigations of Ferredoxin I: The possible role of internal water molecules on the coupled electron proton transfer reaction

2003 ◽  
Vol 124 ◽  
pp. 297 ◽  
Author(s):  
Markus Meuwly ◽  
Martin Karplus
Keyword(s):  
Proton Transfer ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Water Molecules ◽  
Internal Water ◽  
Theoretical Investigations ◽  
Ferredoxin I ◽  
Electron Proton Transfer

scholarly journals Validity and limitations of simple reaction kinetics to calculate concentrations of organic compounds from ion counts in PTR-MS

2019 ◽  
Vol 12 (11) ◽  
pp. 6193-6208 ◽  
Author(s):  
Rupert Holzinger ◽  
W. Joe F. Acton ◽  
William J. Bloss ◽  
Martin Breitenlechner ◽  
Leigh R. Crilley ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Reaction Kinetics ◽  
Transfer Reaction ◽  
Performance Status ◽  
Calibration Method ◽  
Proton Transfer Reaction ◽  
Rural Site ◽  
Water Molecules ◽  
Simple Reaction ◽  
Wide Range

Abstract. In September 2017, we conducted a proton-transfer-reaction mass-spectrometry (PTR-MS) intercomparison campaign at the CESAR observatory, a rural site in the central Netherlands near the village of Cabauw. Nine research groups deployed a total of 11 instruments covering a wide range of instrument types and performance. We applied a new calibration method based on fast injection of a gas standard through a sample loop. This approach allows calibrations on timescales of seconds, and within a few minutes an automated sequence can be run allowing one to retrieve diagnostic parameters that indicate the performance status. We developed a method to retrieve the mass-dependent transmission from the fast calibrations, which is an essential characteristic of PTR-MS instruments, limiting the potential to calculate concentrations based on counting statistics and simple reaction kinetics in the reactor/drift tube. Our measurements show that PTR-MS instruments follow the simple reaction kinetics if operated in the standard range for pressures and temperature of the reaction chamber (i.e. 1–4 mbar, 30–120∘, respectively), as well as a reduced field strength E∕N in the range of 100–160 Td. If artefacts can be ruled out, it becomes possible to quantify the signals of uncalibrated organics with accuracies better than ±30 %. The simple reaction kinetics approach produces less accurate results at E∕N levels below 100 Td, because significant fractions of primary ions form water hydronium clusters. Deprotonation through reactive collisions of protonated organics with water molecules needs to be considered when the collision energy is a substantial fraction of the exoergicity of the proton transfer reaction and/or if protonated organics undergo many collisions with water molecules.

The mechanism of the excited-state multiple proton transfer reaction for 3-Me-2,6-diazaindole in aqueous solution

2018 ◽  
Vol 5 (18) ◽  
pp. 2749-2753 ◽  
Author(s):  
Jin-Dou Huang ◽  
Huipeng Ma
Keyword(s):  
Aqueous Solution ◽  
Excited State ◽  
Potential Energy ◽  
Proton Transfer ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Potential Energy Curves ◽  
Water Molecules

The potential energy curves show that(2,6-aza)Indin aqueous solution undergoes a quadruple-proton transfer reaction with the assistance of three water molecules.

AN AB INITIO STUDY OF PROTON-TRANSFER REACTION IN Be2+(H2O)n AND THE SPATIAL CHANGING FEATURE IN THE FORMATION PROCESS OF HYDROXIDE

2006 ◽  
Vol 05 (01) ◽  
pp. 75-85 ◽  
Author(s):  
XIN LI ◽  
ZHONG-ZHI YANG
Keyword(s):  
Proton Transfer ◽  
Ab Initio ◽  
Formation Process ◽  
Turning Point ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Water Molecules ◽  
Formation Processes ◽  
Classical Turning Point ◽  
Intrinsic Characteristic

The proton-transfer reaction in Be 2+( H 2 O )n is investigated by an ab initio calculation. With an increasing number of water molecules, there are different formation processes of hydroxide, and the reaction barrier is dependent on the cluster size n. By MELD ab initio program and own-coding programs, we have calculated the potential acting on an electron within a molecule, and have investigated the changing of spatial appearance for the formation process of hydroxide, by the molecular intrinsic characteristic contour defined in terms of the classical turning point of electron movement.

scholarly journals Validity and limitations of simple reaction kinetics to calculate concentrations of organic compounds from ion counts in PTR-MS

2019 ◽  
Author(s):  
Rupert Holzinger ◽  
W. Joe F. Acton ◽  
William J. Bloss ◽  
Martin Breitenlechner ◽  
Leigh R. Crilley ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Reaction Kinetics ◽  
Transfer Reaction ◽  
Performance Status ◽  
Calibration Method ◽  
Proton Transfer Reaction ◽  
Rural Site ◽  
Water Molecules ◽  
Simple Reaction ◽  
Wide Range

Abstract. In September 2017, we conducted the Proton-transfer-reaction mass-spectrometry (PTR-MS) Intercomparison campaign at CABauw (PICAB), a rural site in central Netherlands. Nine research groups deployed a total of eleven instruments covering a wide range of instrument types and performance. We applied a new calibration method based on fast injection of a gas standard through a sample loop. This approach allows calibrations on time scales of seconds and within a few minutes an automated sequence can be run allowing to retrieve diagnostic parameters that indicate the performance status. We developed a method to retrieve the mass dependent transmission from the fast calibrations, which is an essential characteristic of PTR-MS instruments, limiting the potential to calculate concentrations based on counting statistics and simple reaction kinetics in the reactor/drift tube. Our measurements show that PTR-MS instruments follow the simple reaction kinetics if operated in the standard range for pressures and temperature of the reaction chamber (i.e. 1–4 mbar, 30–120 ℃, respectively), and a reduced field strength E/N in the range of 100–160 Td. If artefacts can be ruled out, it becomes possible to quantify the signals of uncalibrated organics with accuracies better than ±30 %. The simple reaction kinetics approach produces less accurate results at E/N levels below 100 Td, because significant fractions of primary ions form water hydronium clusters. De-protonation through reactive collisions of protonated organics with water molecules need to be considered when the collision energy is a substantial fraction of the exoergicity of the proton transfer reaction, and/or if protonated organics undergo many collisions with water molecules.

The role of water in the proton transfer reaction mechanism in tryptophan

2010 ◽  
Vol 31 (14) ◽  
pp. 2642-2649 ◽  
Author(s):  
Esteban Vöhringer-Martinez ◽  
Alejandro Toro-Labbé
Keyword(s):  
Reaction Mechanism ◽  
Proton Transfer ◽  
Transfer Reaction ◽  
Proton Transfer Reaction
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