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Journal of Chemical Physics / Volume 124 / Issue 6 / ARTICLES / Condensed Phase Dynamics, Structure, and Thermodynamics: Spectroscopy, Reactions, and Relaxation

J. Chem. Phys. 124, 064507 (2006); http://dx.doi.org/10.1063/1.2162881 (12 pages)

Diabatic free energy curves and coordination fluctuations for the aqueous Ag+/Ag2+ redox couple: A biased Born-Oppenheimer molecular dynamics investigation

Jochen Blumberger1, Ivano Tavernelli2, Michael L. Klein1, and Michiel Sprik3

1Center for Molecular Modeling, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
2Institute of Molecular and Biological Chemistry, Swiss Federal Institute of Technology, Ecole Polytechnique Federal Lausanne (EPFL), Lausanne CH-1015, Switzerland
3Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom

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(Received 25 October 2005; accepted 5 December 2005; published online 14 February 2006)

Biased Born-Oppenheimer molecular dynamics simulations are performed to compute redox potential and free energy curves for the redox half reaction Ag+→Ag2++e− in aqueous solution. The potential energy surfaces of reactant and product state are linearly coupled and the system transferred from the reduced state to the oxidized state by variation of the coupling parameter from 0 to 1. The redox potential is obtained by thermodynamic integration of the average ionization energy of Ag+. Diabatic free energy curves of reduced (R) and oxidized (O) states are obtained to good statistical accuracy by reweighting and combining the set of biased distributions of the ionization energy. The diabatic free energy curves of Ag+ and Ag2+ are parabolic over a wide range of the reaction coordinate in agreement with the linear response assumption that underlies Marcus theory. However, we observe deviations from parabolic behavior in the equilibrium region of Ag+ and find different values for the reorganization free energy of R (1.4 eV) and O (0.9 eV). The computed reorganization free energy of Ag2+ is in good agreement with the experimental estimate of 0.9–1.2 eV obtained from photoelectron spectroscopy. As suggested by our calculations, the moderate deviation from linear response behavior found for Ag+ is likely related to the highly fluxional solvation shell of this ion, which exhibits water exchange reactions on the picosecond time scale of the present molecular dynamics simulation.

© 2006 American Institute of Physics

Article Outline

  1. INTRODUCTION
  2. THEORY
    1. Oxidation free energy
    2. Thermodynamic integration
    3. Diabatic free energy curves
  3. MD METHOD AND SIMULATION DETAILS
    1. Model system
    2. Equilibrium MD
    3. Biased Born-Oppenheimer MD
    4. Electronic structure method
  4. RESULTS AND DISCUSSION
    1. Oxidation free energy
    2. Diabatic free energy curves
    3. Coordination number and ET energy fluctuations
    4. Comparison to experiment
  5. CONCLUSION

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KEYWORDS and PACS

Keywords

silver, positive ions, free energy, reduction (chemical), oxidation, fluctuations, molecular dynamics method, potential energy surfaces, reaction kinetics theory, ionisation potential, photoelectron spectra, solvation, chemical exchanges

PACS

  • 82.20.Kh

    Potential energy surfaces for chemical reactions

  • 82.20.Hf

    Product distribution

  • 82.20.Db

    Transition state theory and statistical theories of rate constants

  • 82.30.Nr

    Association, addition, insertion, cluster formation

  • 82.30.Hk

    Chemical exchanges (substitution, atom transfer, abstraction, disproportionation, and group exchange)

  • 65.20.-w

    Thermal properties of liquids

ARTICLE DATA

Digital Object Identifier
http://dx.doi.org/10.1063/1.2162881

PUBLICATION DATA

ISSN

0021-9606 (print)  
1089-7690 (online)

Publisher

$abstract.society.value is a Member of CrossRef American Institute of Physics

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    A. Warshel and J. K. Hwang, J. Chem. Phys. 84, 4938 (1986)JCPSA6000084000009004938000001.

    G. King and A. Warshel, J. Chem. Phys. 93, 8682 (1990)JCPSA6000093000012008682000001.

    R. A. Kuharski, J. S. Bader, D. Chandler, M. Sprik, M. L. Klein, and R. W. Impey, J. Chem. Phys. 89, 3248 (1988)JCPSA6000089000005003248000001.

    K. Ando, J. Chem. Phys. 106, 116 (1997)JCPSA6000106000001000116000001.

    K. Ando, J. Chem. Phys. 114, 9040 (2001)JCPSA6000114000020009040000001.

    K. Ando, J. Chem. Phys. 114, 9470 (2001)JCPSA6000114000021009470000001.

    K. Ando, J. Chem. Phys. 115, 5228 (2001)JCPSA6000115000011005228000001.

    D. A. Rose and I. Benjamin, J. Chem. Phys. 100, 3545 (1994)JCPSA6000100000005003545000001.

    J. B. Straus, A. Calhoun, and G. A. Voth, J. Chem. Phys. 102, 529 (1995)JCPSA6000102000001000529000001.

    A. Calhoun and G. A. Voth, J. Chem. Phys. 109, 4569 (1998)JCPSA6000109000011004569000001.

    C. Hartnig and M. T. M. Koper, J. Chem. Phys. 115, 8540 (2001)JCPSA6000115000018008540000001.

    R. A. Marcus, J. Chem. Phys. 24, 966 (1956)JCPSA6000024000005000966000001.

    R. A. Marcus, J. Chem. Phys. 24, 979 (1956)JCPSA6000024000005000979000001.

    R. A. Marcus, J. Chem. Phys. 26, 867 (1957)JCPSA6000026000004000867000001.

    R. A. Marcus, J. Chem. Phys. 43, 679 (1965)JCPSA6000043000002000679000001.

    R. A. Marcus, Rev. Mod. Phys. 65, 599 (1993).

    R. Car and M. Parrinello, Phys. Rev. Lett. 55, 2471 (1985).

    I. Tavernelli, R. Vuilleumier, and M. Sprik, Phys. Rev. Lett. 88, 213002 (2002).

    Y. Tateyama, J. Blumberger, M. Sprik, and I. Tavernelli, J. Chem. Phys. 122, 234505 (2005)JCPSA6000122000023234505000001.

    R. Zwanzig, J. Chem. Phys. 22, 1420 (1954)JCPSA6000022000008001420000001.

    J. G. Kirkwood, J. Chem. Phys. 3, 300 (1935)JCPSA6000003000005000300000001.

    R. Vuilleumier and M. Sprik, J. Chem. Phys. 115, 3454 (2001)JCPSA6000115000008003454000001.

    S. Nose, J. Chem. Phys. 81, 511 (1984)JCPSA6000081000001000511000001.

    W. G. Hoover, Phys. Rev. A 31, 1695 (1985).

    G. J. Martyna, M. L. Klein, and M. Tuckerman, J. Chem. Phys. 97, 2635 (1992)JCPSA6000097000004002635000001.

    N. Troullier and J. Martins, Phys. Rev. B 43, 1993 (1991).

    A. D. Becke, Phys. Rev. A 38, 3098 (1988).

    C. Lee, W. Yang, and R. Parr, Phys. Rev. B 37, 785 (1988).

    P. Delahay and A. Dziedzic, J. Chem. Phys. 80, 5793 (1984)JCPSA6000080000011005793000001.

    L. Bernasconi, J. Blumberger, M. Sprik, and R. Vuilleumier, J. Chem. Phys. 121, 11885 (2004)JCPSA6000121000023011885000001.


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