Palestrante: Profa. Dra. Luana Sucupira Pedroza (UFABC)

Resumo:

Understanding the local structure of water at the interfaces of metallic electrodes is a key problem in aqueous-based electrochemistry. A first principles description of all components of the system is the most appropriate methodology to be used, since there is rather limited experimental evidence of the microscopic description of these complex electrochemical interfaces. Notably the system is under an external potential bias, which makes the task of simulating this setup difficult. To correctly compute the effect of an external bias potential applied to electrodes, we combine density functional theory (DFT) and non-equilibrium Green's functions (NEGF) methods. In this work, we apply this methodology to study the electronic properties and atomic forces in a prototypical system of one water molecule at the interface of gold surface. We find that the water molecule is sensitive to the sign and magnitude of the applied bias. We also show that it changes the position and orientati on of the most stable configuration indicating that the external bias plays an important role in the structural properties of the interface.