Gürsoy Emre, Meißner Robert H, Vonbun-Feldbauer Gregor B
Institute for Interface Physics and Engineering, Hamburg University of Technology, 21073 Hamburg, Germany.
Institute of Surface Science, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany.
J Phys Chem Lett. 2025 Jul 3;16(26):6765-6770. doi: 10.1021/acs.jpclett.5c00679. Epub 2025 Jun 24.
Understanding the atomic structure of magnetite-carboxylic acid interfaces is crucial for tailoring nanocomposites involving this interface. We present a Monte Carlo (MC)-based method utilizing iron oxidation state exchange to model magnetite interfaces with tens of thousands of atoms, scales typically inaccessible by electronic structure calculations. Charge neutrality is ensured by the oxidation of Fe ions. The MC approach allows magnetite to adapt to its environment at interfaces without requiring interface-specific rescaling of force-field parameters. This enables a simple, versatile method. By comparing adsorption sites, layer distances, and bond lengths with results from electronic structure calculations and experiments, we validated the accuracy of our method. We found that the oxidation state distribution and, consequently, binding site preference depend on coverage and surface thickness, with a critical thickness signaling the transition from layered to bulk-like oxidation states. The method ensures seamless compatibility with popular biomolecular force fields providing transferability and simplifying the study of magnetite interfaces in general.
了解磁铁矿 - 羧酸界面的原子结构对于定制涉及该界面的纳米复合材料至关重要。我们提出了一种基于蒙特卡罗（MC）的方法，利用铁氧化态交换来模拟具有数万个原子的磁铁矿界面，这是电子结构计算通常无法达到的尺度。通过铁离子的氧化确保电荷中性。MC方法使磁铁矿能够在界面处适应其环境，而无需针对界面特定地重新调整力场参数。这实现了一种简单、通用的方法。通过将吸附位点、层间距和键长与电子结构计算和实验结果进行比较，我们验证了该方法的准确性。我们发现氧化态分布以及因此的结合位点偏好取决于覆盖率和表面厚度，存在一个临界厚度标志着从层状氧化态到块状氧化态的转变。该方法确保与流行的生物分子力场无缝兼容，提供可转移性并总体上简化了对磁铁矿界面的研究。
