Spin density, for

The table gives the computed spin densities for each atom (the value in parenthese following the substituent is its electronegativity). The illustrations are Lewis doi structures showing the primary resonance form for each structure and indicatinj unpaired electrons and lone pairs. 

The second set of illustrations show the spin density plotted on the electron density isosurface the spin density provides the shading for the isodensity surface dark areas indicate positive (excess a) spin density and light areas indicate negative (excess P) spin density. For example, in the allyl radical, the spin density is concentrated around the two terminal carbons (and away from the central carbon). In the Be form, it is concentrated around the substituent, and in acetyl radical, it is centered around the C2 carbon atom. 

Spin density for phenoxy radical shows location of unpaired electron. 

Examine spin densities for the two transition states. Draw a Lewis structure (or sequence of Lewis structures) for each which properly conveys the location(s) of the unpaired electron. 

Next, we discuss the symmetries, bond lengths and spin densities for the anion and cation radicals of fulvalene (XXI) and heptafulvalene (XXIII) using the dynamic theory. We use the semiempirical open-shell SCF MO formalism in conjunction with the variable bond-length technique. 

A practical ramification of this rule is utilized in segregation studies. The most obvious way to study segregation by NMR/MRI is to use two different types of beads, one that is NMR-visible and the other not. However, size segregation studies can be performed by simply using two different sizes of NMR-visible particles because they have different overall spin densities, for the reason stated above. Therefore, the image intensity will depend on the relative concentration of each particle in a voxel. 

Table 5-7. Fe—X distances (A) and Fe spin densities for different states and anions of 11 V S (SCI F >41...

Table 2.1 Hyperfine parameters and spin densities for aromatic radical anions. (Data from ref. 11.)...

Fig. 8. Time decay of normalized light induced spin density for various temperatures. The solid circles are the data points while the solid lines are fits to the data using a stretched exponential time dependence (Jackson and Kakalios, 1988b).

THE LARGE SPIN DENSITIES FOR NORMAL MUONIUM IN DIAMOND AND THE NEAREST-NEIGHBOR... 

The triaryl radicals of germanium exhibit lower g values than their trialkyl counterparts. In part, this arises from increased delocalization of the unpaired spin density onto the aryl rings (and the Ar3Ge radicals do show hyperfme coupling to the ring protons). For example, spin densities for the radicals PhmMe3 mGe, calculated by the Hiickel method (Table 2), reveal that there is a linear correlation between the g value of the radical and... 

TABLE 6. Tin spin densities for the radicals kvSn and R3Sn ... 

Kinetic data for the reaction of the persistent nitroxides such as TEMPO (21) and the (CF3)2NO- radical with Ph3GeH and Bu3GeH, respectively, were determined by ESR spectroscopy.61,72 The fluorinated nitroxide was more than four orders of magnitude more reactive than TEMPO. On the other hand, the similar reactivities of the (CF3)2NO- and PhCMe200-radical toward Bu3GeH are expected because both the thermochemistries and spin densities for these two radicals are rather similar.72,73... 

Among the quantities which have proven of value as graphical models are the molecular orbitals, the electron density, the spin density (for radicals and other molecules with unpaired electrons), the electrostatic potential and the local ionization potential. These may all be expressed as three-dimensional functions of the coordinates. One way to display them on a two-dimensional video screen (or on a printed page) is to define a surface of constant value, a so-called isovalue surface or, more simply, isosurface. ... 

Selected 17 O Hyperfine Constants and Total Spin Densities for Diatomic Oxygen Species with Equivalent Oxygen Nuclei... 

Using a perturbation treatment, McLachlan has derived an expression for spin densities that corrects the Huckel spin densities for configuration interaction effects 106) p, = Ci02 - 1m,Coa2, where A. is a constant and 7Ta is an atom-atom polarizability. 

We have found in our work that these parameters give excellent agreement with experimental spin densities for trimethylsilyl-and trimethylgermyl-substituted aniline radical cations (29, 28). 

Spin density for 2-methyl-2-butanol radical cation shows location of impaired electron. 

At the CNDO/2 level Davies 50) has calculated spin densities for some fluorinated nitrobenzenes and shown that they follow the general pattern of hyperfine coupling constants. 

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