A precision paramagnetic resonance spectrometer

Magnetic resonance in Kazan and in Oxford

“…The construction of an apparatus for magnetic resonance using atomic beams [45] was foUowed by another for precision EPR measurements on free atoms [46], with stabilization of both frequency and magnetic field, giving an accuracy of 1 to 2 ppm. These made possible interesting compa¡ at Oxford between some atoms and ions in S-states.…”

“…In an early use of the precision EPR spectrometer [46], free atoms of 127I were generated in the microwave cavity by photo-dissociation of iodine vapour [51]. Six transitions within the 2P3/z ground state were fitted to the hyperfine structure constants known from atomic beam measurements.…”

Electron Spin Resonance Spectra of Oriented Radicals

“…Wmsm, -g?H<¡Ms + AMiMs (Eq. 10) Electron spin resonance transitions between these energy levels are governed by the selection rules AMs = ±1, and AMt = 0. The hyperfine interaction constant A determines the separation between hyperfine lines corresponding to successive Mr-values.…”

Electron Paramagnetic Resonance in Gases

“…These measurements in Oxford were made using a precision EPR spectrometer built at my suggestion in 1954/5 by Bowers, Kamper and Knight (34). Stabilization was provided, both for the frequency source and the magnet.…”