Magnetic Resonances of Protons in Ethyl Alcohol

Abstract

Studies have been made of the proton magnetic resonances of ethyl alcohol under considerably higher resolution than has heretofore been reported. A description of the apparatus includes details of construction of a large permanent magnet, with some of the considerations directed toward improvement of resolution by reduction of field inhomogeneities. Also, the features of a specially designed nuclear magnetic resonance head are described. This head is provided with facilities for spinning the sample for the further reduction of the effective field inhomogeneity. Considerations of stability of the field and the radio-frequency components are briefly discussed.Recordings of the observed spectra of ethyl alcohol are shown and are related to the predictions of calculations based on the use of a Hamiltonian which includes a particularly simple form of spin-spin interaction. The features of the spectra are finally resolved to about \textonehalf{} cps in 30 Mc/sec, and the agreement between predicted and observed structures is reasonably good.The spectra were found to be strongly modified by the presence or almost complete absence of contamination of the ethyl alcohol by ${\mathrm{H}}^{+}$ or O${\mathrm{H}}^{\ensuremath{-}}$ ions. The effect is attributed to an exchange process involving the hydroxyl proton of the ethyl alcohol molecule. The characteristic times between exchange events have been approximately determined for specified concentrations of ${\mathrm{H}}^{+}$ and O${\mathrm{H}}^{\ensuremath{-}}$ ions up to the order of ${10}^{\ensuremath{-}5}$ normal.