Accession Number : AD0460370


Title :   ELECTRON- AND PROTON-TRANSFER BY THE GROTTHUSS MECHANISM IN AQUEOUS SOLUTION AND IN BIOLOGICAL SYSTEMS.


Descriptive Note : Technical rept.,


Corporate Author : LITTLE (ARTHUR D) INC CAMBRIDGE MA


Personal Author(s) : Horne, R A ; Courant, R A ; Johnson, D S


Report Date : 01 Apr 1965


Pagination or Media Count : 28


Abstract : The Fe(II)-Fe(III) electron-exchange reaction and certain long-range biological redox reactions involve the transfer of electrons by a Grotthusstype mechanism over water bridges. The Grotthuss mechanism is also responsible for the anomalously great electrical conductivity acidic aqeuous solutions. At ordinary pressures the rate-determining step of the Grotthuss mechanism is the rotation of H2O, possibly H3O+, and not the actual proton flip itself. The Grotthuss mechanism is confined to the 'free', rotatable, monomeric water between the Frank-Wen clusters in liquid water and avoids areas of relative order. The concentration dependence of protonic conduction can be represented by an equation based upon a cube root of concentration extrapolation and containing Arrhenius terms in which the activation energies are those for the rotation of and the formation of 'holes' in the solvent water. Thus chemical energy and/or electrical energy can be transmitted rapidly over relatively great distances by the Grotthuss mechanism. Such processes are involved in a variety of phenomena of biological significance, examples being muscular contraction and the chemistry of the respiratory pigments. (Author)


Descriptors :   *OXIDATION REDUCTION REACTIONS , REACTION KINETICS , BIOCHEMISTRY , TRANSPORT PROPERTIES , ELECTRONS , PROTONS , IRON , RESPIRATION , CELLS(BIOLOGY) , MUSCLES , CONTRACTION , ELECTRICAL CONDUCTIVITY , EXCHANGE REACTIONS , WATER , MOLECULAR ASSOCIATION , HEAT OF ACTIVATION , PRESSURE , TEMPERATURE , MASS , ROTATION , ELECTRIC FIELDS , HEMOGLOBIN , ELECTROCHEMISTRY


Distribution Statement : APPROVED FOR PUBLIC RELEASE