Abstract
Evidence is obtained from ESR spectra of potassium metal solutions in ethylamine and in a mixed ethyl- amine-methylamine solvent to show that the central component in these spectra may be attributed to the solvated electron in very dilute solutions, but that in more concentrated metal solutions this single line res- onance must be assigned to an ion pair of the solvated electron with K+. As a consequence of this assign- ment, the temperature dependence of the metal nuclear hyperfine coupling constant, om, cannot arise on account of a rapid equilibrium between the ion pair and isomeric species of metal with fixed values of the hyperfine coupling constant. In addition, the shape of the hyperfine lines for pure ethylamine solutions is found to deviate appreciably from the Lorentzian shape expected if such a rapid equilibrium would be op- erative. However, the facts available are consistent with the idea that the temperature dependence of om arises on account of the presence of thermally accessible vibrational states with a distribution of values of om-