Hyperfine structure investigations by

Hyperfin structure investigations by the atomic beam technique 

Measurements at low fields, Rjl-igB Aj. The measurement of the frequencies of the AF=0, AMp= 1 transitions in low magnetic fields leads to an unambiguous determination of the nuclear spin I, as equation (18.24) demonstrates. 

once the nuclear spin is known, the electronic Landd factor, gj, can be determined to high precision. In the early atomic beam experiments there was, however, little 

Relativistic quantum-electrodynamic calculations then showed that the anomalous electron g-factor is modified by the vacuum fluctuations of the radiation field and should be given by 

Thus atomic beam experiments provide important information about the value of the fine-structure constant a. 

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