Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 9: Solid-Liquid Interfaces: Structure, Spectroscopy I
O 9.4: Talk
Monday, March 20, 2017, 11:15–11:30, WIL C307
Optical fingerprints of solid-liquid interfaces: a joint ATR-IR and first principles investigation — •Lei Yang1, Fang Niu1, Stefanie Tecklenburg1, Marc Pander1, Simantini Nayak1, Andreas Erbe1, Stefan Wippermann1, Francois Gygi2, and Giulia Galli3 — 1MPI Eisenforschung — 2UC Davis — 3U Chicago
Despite the importance of understanding the structural and bonding properties of solid-liquid interfaces for a wide range of (photo-)electrochemical applications, there are presently no experimental techniques available to directly probe the microscopic structure of solid-liquid interfaces. To develop robust strategies to interpret experiments and validate theory, we carried out attenuated total internal reflection (ATR-IR) spectroscopy measurements and ab initio molecular dynamics (AIMD) simulations of the vibrational properties of interfaces between liquid water and well-controlled prototypical semiconductor substrates. We show the Ge(100)/H2O interface to feature a reversible potential-dependent surface phase transition between Ge-H and Ge-OH termination. The Si(100)/H2O interface is proposed as a model system for corrosion and oxidation processes. We performed AIMD calculations under finite electric fields, revealing different pathways for initial oxidation. These pathways are predicted to exhibit unique spectral signatures. A significant increase in surface specificity can be achieved utilizing an angle-dependent ATR-IR experiment, which allows to detect such signatures at the interfacial layer and consequently changes in the hydrogen bond network. Funding from DOE-BES Grant DE-SS0008939 and the DFG (RESOLV, EXC 1069) are acknowledged.