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<div>'''McConnell equation''' describes the proportional dependence of the [[hyperfine structure|hyperfine splitting constant]] <math>a</math> on the spin density <math>\rho</math> (the probability of an unpaired electron being on a particular atom) in aromatic radical compounds such as [[benzene]] [[radical anion]] <math>C_6H_6^-</math>.<br />
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<math>a=Q \rho</math><br />
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<math>Q</math> is an empirical constant that can range from 2.0 to 2.5 mT.<br />
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== History ==<br />
The equation is named after [[Harden M. McConnell]] of [[Stanford University]], who first presented it in 1956 in an article in the [[Journal of Chemical Physics]].<ref>McConnell, H. M., 1956, J. Chem. Phys., 24, 764. [http://dx.doi.org/10.1063/1.1742605 DOI]</ref><br />
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== References ==<br />
[[Peter Atkins]], Julio de Paula, ''Atkins' Physical Chemistry'', 9th ed., [[Oxford University Press]], Oxford, 14, 556<br />
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[[Category:Chemical physics]]</div>88.215.22.246