Studies in Paramagnetic Resonance

Citation

Humphrey, Floyd Bernard (1956) Studies in Paramagnetic Resonance. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/RGNN-0K54. https://resolver.caltech.edu/CaltechETD:etd-03242004-114132

Abstract

A paramagnetic resonance spectrometer has been designed and constructed which is particularly adaptable to problems in the field of chemistry. It is a wide range, high resolution instrument suitable for investigating the spectrum of paramagnetic substances from g = 0.7 to g = 7.5 with resonance lines from a fraction of a gauss to 1000 gauss wide. Spectra can be observed at temperatures from room temperature to liquid helium temperature using single crystals, powders, or solutions as samples. The sensitivity is such that 10[superscript 15] paramagnetic atoms are needed per sample. The spectrum of gadolinium ion in a micro-crystalline sample of ceric oxide has been investigated. The observed resonance line contained structure that could not be resolved with extreme magnetic dilution (100,000:1) low temperature (4.5[degrees]K) or both. An explanation for this structure is suggested. The value of g for the line was measured at two different magnetic field strengths, as was the zero field splitting. An anomalous shift in the direction of the free ion value of g was found when the field was changed from 3400 gauss to 8600 gauss. The spectrum of manganous ion in a micro-crystalline sample of aragonite was observed at both 3400 gauss and 8600 gauss. An isotropic hyperfine structure of 6 lines was observed. A precise comparison between theory and experiment was made showing excellent agreement. Work on other compounds is also reported.

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