## Abstract

Flash photolysis of sodium pyrenide, $\pi \overline{.}$, Na$^{+}$, in THF demonstrated that three transients are formed in the process: solvated electrons, e$^{-}$, their ion pairs with Na$^{+}$ cations, e$^{-}$, Na$^{+}$, and sodium atoms, Na degrees. The rate constants of the following reactions were determined: e$^{-}$, Na$^{+}+\pi \rightarrow $ $\pi \overline{.}$, Na$^{+}$ $k_{3}=1.7\times 10^{10}$ l mol$^{-1}$ s$^{-1}$, (3) e$^{-}+\pi \rightarrow $ $\pi \overline{.}$ $k_{4}=7\times 10^{10}$ l mol$^{-1}$ s$^{-1}$, (4) Na$^{\circ}+\pi \rightarrow $ $\pi \overline{.}$, Na$^{+}$ $k_{5}=1\times 10^{10}$ l mol$^{-1}$ s$^{-1}$, (5) e$^{-}$, Na$^{+}\rightarrow $ Na$^{\circ}$, $k_{6}=4\times 10^{3}$ s$^{-1}$. (6) The dissociation constant of e$^{-}$, Na$^{+}$ pair into e$^{-}$ and Na$^{+}$ was estimated to be $0.3\times 10^{-7}$ mol/l in THF at about 20 degrees C, and the rate constant of association of e$^{-}$ with Na$^{+}$ cations was estimated as $4\times 10^{11}$ l mol$^{-1}$ s$^{-1}$.