Solvent-dependent rate constants of muonium atom reactions

2003 ◽  
Vol 81 (2) ◽  
pp. 175-178
Author(s):  
Stefan Karolczak ◽  
Hugh A Gillis ◽  
Gerald B Porter ◽  
David C Walker
Keyword(s):  
Rate Constants ◽  
Muon Spin ◽  
Isotope Effects ◽  
Reaction Rates ◽  
Muon Spin Rotation ◽  
Muonium Atom ◽  
Dependent Rate ◽  
Kinetic Isotope ◽  
Rotation Technique ◽  
Reactive Atom

The rates of reaction of muonium atoms with solutes, ionic and organic, were studied in solvents of wildly differing polarities (water, methanol, and hexane) and their rate constants were compared, where possible. In these reactions — which are those of a highly reactive atom, an isotope of hydrogen — it transpires that the reaction rates are higher in solvents in which the solute is more soluble and muonium diffuses faster. This study leads to various kinetic-solvent-effect ratios and to the observation of the reaction of muonium with free radicals being among the fastest reactions recorded so far between two neutral species in solution.Key words: muonium atoms, kinetic isotope effects, solvent-dependent rates, non-aqueous solvents, muon spin rotation technique.

Kinetic isotope effects from reactions of muonium atoms in water with various ketones, and acetaldehyde: contrasts with hydrogen atoms

1997 ◽  
Vol 75 (1) ◽  
pp. 74-76 ◽  
Author(s):  
John M. Stadlbauer ◽  
Krishnan Venkateswaran ◽  
David C. Walker
Keyword(s):  
Hydrogen Atom ◽  
Muon Spin ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Muon Spin Rotation ◽  
Hydrogen Atoms ◽  
Tert Butyl ◽  
Kinetic Isotope ◽  
Dilute Aqueous Solutions ◽  
Butyl Ketone

This paper presents data showing that in dilute aqueous solutions of butanone, 3-pentanone, cyclohexanone, di-tert-butyl ketone, and acetaldehyde the addition reaction of muonium atoms occurs with a rate constant close to 1 × 108 M−1 s−1. The same value was obtained previously for acetone. Thus the reaction rate is virtually independent of the group attached to the C=O, be it a methyl, methylene, tert-butyl, or even a hydrogen atom. This is in sharp contrast to the reactivity of ordinary 1H atoms, whose rate constants are much slower and dependent on adjacent groups. In fact muonium and 1H react by different mechanisms, to form different products, so their rate ratio represents a complex kinetic isotope effect. Keywords: kinetic isotope effects, muonium atoms, muon spin rotation, ketones, hydrogen atom reactions.

Muonium addition to vinyl monomers

1981 ◽  
Vol 59 (23) ◽  
pp. 3261-3266 ◽  
Author(s):  
J. M. Stadlbauer ◽  
B. W. Ng ◽  
D. C. Walker ◽  
Y. C. Jean ◽  
Y. Ito
Keyword(s):  
Rate Constants ◽  
Hyperfine Coupling ◽  
Isotope Effects ◽  
Hyperfine Coupling Constant ◽  
Coupling Constant ◽  
Methyl Radical ◽  
Muonium Atom ◽  
Kinetic Isotope ◽  
The Fourier Transform ◽  
Two Peaks

The chemical rate constants for the addition of the muonium atom (Mu) across the vinyl double bonds of acrylamide, acrylic acid, acrylonitrile, methylmethacrylate, and styrene were determined in aqueous solution; they are, respectively, kM = 1.9 × 1010M−1s−1, 1.6 × 1010M−1s−1, 1.1 × 1010M−1s−1, 9.5 × 109 M−1s−1, and 1.1 × l09 M−1s−1. Since muonium can be considered a very light isotope of hydrogen, the kinetic isotope effects, kM/kH, for acrylamide (1.1) and acrylonitrile (2.8) were calculated. The muonium rate constants of these monomers are also compared to those of hydroxyl and methyl radical additions where available. The muonium substituted free radical formed by reaction with styrene is represented by two peaks in the Fourier Transform of the μSR spectrum at 500, 1500, and 2500 G with a hyperfine coupling constant of 213.5 MHz. This spectrum shows that Mu addition to styrene occurs at the vinyl bond only and not at the benzene ring.

HO + CO Reaction Rates and H/D Kinetic Isotope Effects: Master Equation Models with ab Initio SCTST Rate Constants

2013 ◽  
Vol 117 (5) ◽  
pp. 821-835 ◽  
Author(s):  
Ralph E. Weston ◽  
Thanh Lam Nguyen ◽  
John F. Stanton ◽  
John R. Barker
Keyword(s):  
Ab Initio ◽  
Master Equation ◽  
Rate Constants ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Reaction Rates ◽  
Kinetic Isotope

The ion–molecule reactivity of the positive muon molecular ions HeMu+ and NeMu+

1988 ◽  
Vol 66 (8) ◽  
pp. 2018-2024 ◽  
Author(s):  
D. J. Arseneau ◽  
D. G. Fleming ◽  
M. Senba ◽  
I. D. Reid ◽  
D. M. Garner
Keyword(s):  
Muon Spin ◽  
Reaction Rates ◽  
Molecular Ions ◽  
Muon Spin Rotation ◽  
Rare Gas ◽  
Molecule Reaction ◽  
Internal Excitation ◽  
Muon Transfer ◽  
Rotation Technique ◽  
Total Capture

Thermal (300 K) ion–molecule reaction rates are measured, using the µSR (muon spin rotation) technique, for the muonated rare gas molecular ions HeMu+ and NeMu+ reacting with NO, O2, N2O, NH3, CF4, C2H4, TMS, and CH3NO2. In almost every case (excepting O2), both charge transfer (ke) and muon transfer (kµ) contribute to the reaction rate. Reaction is believed to occur from ro-vibrational excited states, [HeMu+]* and [NeMu+]*, due to the poor efficiency of He and Ne moderators for collisional deactivation. The total experimental rate constants, kexp = kµ + ke, are generally in excellent agreement with total capture rates predicted by the simple ADO theory, regardless of the degree of internal excitation. Comparisons with literature values for corresponding protonated ion reaction rates with O2 and C2H4 reveal little or no isotope effect, although it is noted that these reactions are dominated by proton transfer, in contrast to the µSR results.

A Theoretical Analysis of Rate Constants and Kinetic Isotope Effects Corresponding to Different Reactant Valleys in Lactate Dehydrogenase

2006 ◽  
Vol 128 (51) ◽  
pp. 16851-16863 ◽  
Author(s):  
Silvia Ferrer ◽  
Iñaki Tuñón ◽  
Sergio Martí ◽  
Vicente Moliner ◽  
Mireia Garcia-Viloca ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Theoretical Analysis ◽  
Rate Constants ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope

Ab initio predictions and experimental confirmation of large tunneling contributions to rate constants and kinetic isotope effects for hydrogen atom transfer reactions

1986 ◽  
Vol 108 (12) ◽  
pp. 3515-3516 ◽  
Author(s):  
Bruce C. Garrett ◽  
Donald G. Truhlar ◽  
Joel M. Bowman ◽  
Albert F. Wagner ◽  
Daniel. Robie ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Ab Initio ◽  
Rate Constants ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Hydrogen Atom Transfer ◽  
Experimental Confirmation ◽  
Transfer Reactions ◽  
Atom Transfer ◽  
Kinetic Isotope

Variational transition state theory rate constants and H/D kinetic isotope effects for CH 3 + CH 3 OCOH reactions

2019 ◽  
Vol 41 (3) ◽  
pp. 231-239 ◽  
Author(s):  
Edson F. V. Carvalho ◽  
Guilherme D. Vicentini ◽  
Tiago Vinicius Alves ◽  
Orlando Roberto‐Neto
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
State Theory ◽  
Variational Transition State Theory ◽  
Kinetic Isotope ◽  
Variational Transition State

Rate constants and kinetic isotope effects for Cl+CH4→ClH+CH3: a comparison between LSC-IVR and statistical theories

2002 ◽  
Vol 360 (1-2) ◽  
pp. 59-64 ◽  
Author(s):  
Emilio Martı́nez-Núñez ◽  
Antonio Fernández-Ramos ◽  
Saulo A Vázquez ◽  
Miguel A Rı́os
Keyword(s):  
Rate Constants ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope

Dynamics calculations for the Cl+C2H6 abstraction reaction: Thermal rate constants and kinetic isotope effects

2003 ◽  
Vol 118 (14) ◽  
pp. 6280-6288 ◽  
Author(s):  
A. Fernández-Ramos ◽  
E. Martı́nez-Núñez ◽  
J. M. C. Marques ◽  
S. A. Vázquez
Keyword(s):  
Rate Constants ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Thermal Rate Constants ◽  
Abstraction Reaction
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