Bias-dependent local structure of water molecules at a metallic interface

Autor(es)

Pedroza, Luana S. ^{[1, 2]} ; Brandimarte, Pedro ^{[3, 4]} ; Rocha, Alexandre Reily ^[5] ; Fernandez-Serra, M. -V. ^{[6, 7]}

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210170 Santo Andre, SP - Brazil

^[2] Univ Estadual Paulista, Inst Fis Teor, ICTP South Amer Inst Fundamental Res, BR-01140070 Sao Paulo, SP - Brazil

^[3] Ctr Fis Mat, Donostia San Sebastian 20018, Gipuzkoa - Spain

^[4] Donostia Int Phys Ctr, Donostia San Sebastian 20018, Gipuzkoa - Spain

^[5] Univ Estadual Paulista, Inst Fis Teor, BR-01140070 Sao Paulo, SP - Brazil

^[6] SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 - USA

^[7] SUNY Stony Brook, Inst Adv Computat Sci, Stony Brook, NY 11794 - USA

• Tipo de documento: Artigo Científico
• Fonte: CHEMICAL SCIENCE; v. 9, n. 1, p. 62-69, JAN 7 2018.
• Citações Web of Science: 4

Resumo

Understanding the local structure of water at the interfaces of metallic electrodes is a key issue in aqueousbased electrochemistry. Nevertheless a realistic simulation of such a setup is challenging, particularly when the electrodes are maintained at different potentials. To correctly compute the effect of an external bias potential applied to truly semi-infinite surfaces, we combine Density Functional Theory (DFT) and NonEquilibrium Green's Function (NEGF) methods. This framework allows for the out-of-equilibrium calculation of forces and dynamics, and directly correlates to the chemical potential of the electrodes, which is introduced experimentally. In this work, we apply this methodology to study the electronic properties and atomic forces of a water molecule at the interface of a gold surface. We find that the water molecule tends to align its dipole moment with the electric field, and it is either repelled or attracted to the metal depending on the sign and magnitude of the applied bias, in an asymmetric fashion. (AU)

• Processo FAPESP: 11/11973-4 - ICTP Instituto Sul-Americano para Pesquisa Fundamental: um centro regional para física teórica
• Beneficiário: Nathan Jacob Berkovits
• Linha de fomento: Auxílio à Pesquisa - Temático