Benzene magnetic field effect

Figure 16.15—Electron ionisation (El). The collision of an electron with a sample molecule m produces ionisation that leads to formation of a parent ion and fragment ions. Ions that result from the reaction m/ and raj are also called secondary or daughter ions. Since they carry no charge, neutral fragments produced during decomposition, (ra, m[ and m ), are not detected. An illustration of electron ionisation of benzene is shown. Also shown is a schematic of the ionisation chamber (ion source). Using a parallel magnetic field can increase the effective path of an electron in the ion source, which increases ionisation efficiency.

Figure 2 shows the magnetic field dependence of the ratio of the yields of symmetrical (2) and unsymmetrical (1) products for the reaction of benzyl chloride with Et3GeNa in benzene17. As earlier observed in the reactions of alkyllithiums with dichlorodiphenylmethane9, the field dependence pattern qualitatively reflects two basic mechanisms of radical pair theory — HFI and Ag mechanisms. In this particular case, the cage effects in nonviscous media (benzene) create the necessary prerequisites for the... 

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