Accession Number:

ADA279279

Title:

Quantum Simulation of Heterogeneous Electron Transfer Free Energies at the Water-Metal Interface

Descriptive Note:

Technical rept. May 1993-May 1994

Corporate Author:

PENNSYLVANIA UNIV PHILADELPHIA DEPT OFCHEMISTRY

Personal Author(s):

• Straus, Jay B.
• Voth, Gregory A.

Report Date:

1994-05-06

Pagination or Media Count:

38.0

Abstract:

The free energy for electron transfer is studied for the Fe2 Fe3 charge transfer system at the water-Pt111 interface. Classical adiabatic free energy curves are calculated along with an adiabatic curve based on the Anderson-Newns Hamiltonian. Reactive flux calculations are then performed on this curve to determine the effect of recrossings on the classical rate constant. These effects are not found to be large Kappa approx. 0.6 The solvent model is then extended to a quantum mechanical path integral version and quantum adiabatic free energy curves are calculated. The resulting quantum effects are found to be quite significant, illustrating that the same electrode overpotential does not necessarily result from the same free energy curves for the classical and quantum mechanical solvent models. These results suggest that classical models for water may not be adequate, or at least need to be modified, for accurate simulations of heterogeneous electron transfer.

Descriptors:

• *SIMULATION
• *METALS
• *INTERFACES
• *WATER
• *QUANTUM THEORY
• *CHARGE TRANSFER
• *ELECTRON TRANSFER
• *FREE ENERGY
• IONS
• MODELS
• COMPUTERS
• CHEMICALS
• DYNAMICS
• INTEGRALS
• PATHS
• RATES
• ELECTROCHEMISTRY
• ELECTRODES
• CONSTANTS
• SOLVENTS
• SEPARATION
• PLATINUM
• POLARITY
• ADIABATIC CONDITIONS
• CURVES(GEOMETRY)

Subject Categories:

• Physical Chemistry
• Computer Programming and Software
• Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE