Electrons in solutions

THE possibility of a stable bound state of the electron in water and in similar media is of importance in many fields of chemistry in which electron-transfer phenomena play a part. In photochemistry and in radiation chemistry particularly, there have been recently several discussions of this problem¹. Since no definite conclusions have been reached, we have recently reconsidered the problem (Bareli, K., and Stein, G., unpublished work). Several independent methods used by us point to the same conclusion, namely, that the aqueous medium does possess an electron affinity. Regarding the quantitative value of the energy of binding, two hypothetical bound states of the electron in water were indicated. Some of the methods used by us indicated that in the first of these, which may be denoted by e_aq., the electron is bound with an energy of approximately 25 kcal./ mole. In the other hypothetical state, which was obtained by the use of a different approach and which may be denoted by H₂O_aq.^-, the electron would be bound with an energy of the order of 70 kcal./mole.