REORGANIZATION OF THE MEDIUM AND LOCAL VIBRATIONS IN ELECTRODE-REACTIONS OF ELECTRON-PROTON TRANSFER

An electron-proton transfer reaction at the interphase between a metal and a polarizable medium exhibiting long-range outer sphere and short -range inner sphere interactions is considered within the spin-boson H amiltonian formalism, which enables one to go beyond the common, doubl e adiabatic, approximation. Electron interactions with the medium are separated into two parts corresponding to linear coupling of the elect ron with the medium (bath I), and with the proton, which in turn inter acts with the internal degrees of freedom of the reaction complex (bat h II). The rate constants are derived for the cases of low and high te mperatures with respect to the proton vibration frequency (quantum and classical local vibrations) and for an arbitrary ratio of reorganizat ion energies of the medium and the reaction complex. A modified Arrhen ius law is found for the case of quantum proton oscillation. Hydrogen ion discharge is considered as an example. Electrochemical desorption of hydrogen is suggested to proceed through hydrogen tunneling in non- reorganized media.