Electron Tunneling in Photoinduced Decay of Trapped Electrons

4 Electron Tunneling in Photoinduced Decay of Trapped Electrons 

As is known from the literature [59 a], illumination of frozen solutions containing trapped electrons in the e,7 absorption band results in a decrease in the concentration of e,7. It is also well known that, for water-alkaline glasses, with such illumination, a transition of an electron from a trap into the conduction 

If illumination is started long enough after the end of irradiation that produced e,7, then the kinetics of a tunneling reaction in the presence of light-induced electron diffusion and under the condition of random spatial distribution of acceptor particles, provided n N and x g t, can be described by the expression [60]  

Here n and N are the concentrations of et7 and the acceptors, respectively, t is the time elapsed from the moment the light is switched on, x 1 is the probability of the transition of an electron to a quasi-free (mobile) state per unit time under the action of light, RT = (ae/2) In v(,x is the distance of electron tunneling from a trap to an acceptor within the time x. 

Equation (30) has a simple physical meaning. Indeed, the right hand side of Eq. (30) is the probability that the electron will not get into the volume NV, = (4/3) JtR/N as a result of light-induced jumpwise migration through the sample, and t/x is the number of jumps made within the time t. As follows from the definition of R the entry of the electron into a volume VT around an acceptor leads, within the time x of its residence in this volume, to its tunnel decay on an acceptor with a probability virtually equal to unity. 

---