TY - JOUR

T1 - The effect of intramolecular quantum modes on free energy relationships for electron transfer reactions

A1 - Ulstrup,Jens

A1 - Jortner,Joshua

AU - Ulstrup,Jens

AU - Jortner,Joshua

PB - American Institute of Physics

PY - 1975

Y1 - 1975

N2 - A general quantum mechanical description of exothermic electron transfer reactions is formulated by treating such reactions as the nonradiative decay of a ''supermolecule'' consisting of the electron donor, the electron acceptor, and the polar solvent. In particular, the role of the high-frequency intramolecular degrees of feedom on the free energy relationship for series of closely related reactions was investigated for various model systems involving displacement of potential energy surfaces, frequency shift, and anharmonicity effects. The free energy plots are generally found to pass through a maximum and to be asymmetric with a slower decrease in the transition probability with increasing energy of reaction. For high-frequency intramolecular modes this provides a rationalization of the experimental observation of ''activationless'' regions. Isotope effects are discussed as also are the oscillatory free energy relationships, predicted for low temperatures and high frequencies, and which are analogous to the vibrational structure in optical transitions. The Journal of Chemical Physics is copyrighted by The American Institute of Physics.

AB - A general quantum mechanical description of exothermic electron transfer reactions is formulated by treating such reactions as the nonradiative decay of a ''supermolecule'' consisting of the electron donor, the electron acceptor, and the polar solvent. In particular, the role of the high-frequency intramolecular degrees of feedom on the free energy relationship for series of closely related reactions was investigated for various model systems involving displacement of potential energy surfaces, frequency shift, and anharmonicity effects. The free energy plots are generally found to pass through a maximum and to be asymmetric with a slower decrease in the transition probability with increasing energy of reaction. For high-frequency intramolecular modes this provides a rationalization of the experimental observation of ''activationless'' regions. Isotope effects are discussed as also are the oscillatory free energy relationships, predicted for low temperatures and high frequencies, and which are analogous to the vibrational structure in optical transitions. The Journal of Chemical Physics is copyrighted by The American Institute of Physics.

UR - http://link.aip.org/link/?JCPSA6/63/4358/1

U2 - 10.1063/1.431152

DO - 10.1063/1.431152

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 10

VL - 63

SP - 4358

EP - 4368

ER -