scholarly journals Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical

2015 ◽  
Vol 143 (24) ◽  
pp. 244306 ◽  
Author(s):  
Ahmad Y. Adam ◽  
Andrey Yachmenev ◽  
Sergei N. Yurchenko ◽  
Per Jensen
Keyword(s):  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Coupling Constant ◽  
Methyl Radical ◽  
Isotropic Hyperfine Coupling

Electron Spin Resonance Linewidth Studies of Vanadyl Tetraphenylporphyrin

1993 ◽  
Vol 58 (6) ◽  
pp. 1294-1298
Author(s):  
Ali H. Al-Mowali ◽  
Alhan D. Girgees
Keyword(s):  
Electron Spin Resonance ◽  
Unpaired Electron ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Esr Spectra ◽  
Coupling Constant ◽  
Electron Spin Resonance Linewidth ◽  
Isotropic Hyperfine Coupling ◽  
Spin Resonance ◽  
Line Widths

The linewidths of the hyperfine components of the ESR spectra of vanadyl tetraphenylporphyrin in liquid toluene have been measured as a function of temperature and analyzed in detail. This has allowed the separate contributions to the observed ESR line widths from spin rotational, g tensor anisotropy, hyperfine anisotropy and unresolved nitrogen hyperfine coupling to be evaluated. These results have been used to estimate the size of the nitrogen isotropic hyperfine coupling constant and thus the extent of delocalization of the unpaired electron onto the nitrogen atoms.

A Study of the Effect of Solvent and Temperature on the Electron Paramagnetic Resonance Parameters and Linewidths of Copper(II)bis(Diethyldithiocarbamate)

1974 ◽  
Vol 52 (24) ◽  
pp. 4016-4024 ◽  
Author(s):  
F. Geoffrey Herring ◽  
Robert L. Tapping
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Rotational Correlation Time ◽  
Coupling Constant ◽  
Paramagnetic Resonance ◽  
Axial Ligation ◽  
Effect Of Solvent ◽  
Isotropic Hyperfine Coupling ◽  
Electron Paramagnetic

The effect of varying solvent and temperature on the e.s.r. parameters and linewidths of copper(II) bis(diethyldithiocarbamate) has been studied. The temperature and solvent dependences of the isotropic hyperfine coupling constant (a0) have been interpreted in terms of vibronic and axial ligation effects. The rotational correlation time, τR, of Cu(DEDC)2 has been measured in the solvents employed. The values of τR measured at 300 K have been used to obtain the anisotropic interaction parameter, κ, which is found to correlate roughly with the dipole moment and molar refractivity of the solvent.

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.

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