Activation entropy of electron transfer reactions

Anatoli A. Milischuk, Dmitry Matyushov, Marshall D. Newton

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

We report microscopic calculations of free energies and entropies for intramolecular electron transfer reactions. The calculation algorithm combines the atomistic geometry and charge distribution of a molecular solute obtained from quantum calculations with the microscopic polarization response of a polar solvent expressed in terms of its polarization structure factors. The procedure is tested on a donor-acceptor complex in which ruthenium donor and cobalt acceptor sites are linked by a four-proline polypeptide. The reorganization energies and reaction energy gaps are calculated as a function of temperature by using structure factors obtained from our analytical procedure and from computer simulations. Good agreement between two procedures and with direct computer simulations of the reorganization energy is achieved. The microscopic algorithm is compared to the dielectric continuum calculations. We found that the strong dependence of the reorganization energy on the solvent refractive index predicted by continuum models is not supported by the microscopic theory. Also, the reorganization and overall solvation entropies are substantially larger in the microscopic theory compared to continuum models.

Original languageEnglish (US)
Pages (from-to)172-194
Number of pages23
JournalChemical Physics
Volume324
Issue number1 SPEC. ISS.
DOIs
StatePublished - May 9 2006

Keywords

  • Electron transfer
  • Entropy of activation
  • Polar liquids
  • Structure factors
  • Theory of solvation

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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