Gürsoy, EmreEmreGürsoyMeißner, RobertRobertMeißnerVonbun-Feldbauer, GregorGregorVonbun-Feldbauer2025-07-162025-07-162025-07-03Journal of Physical Chemistry Letters 16 (26): 6765−6770 (2025)https://hdl.handle.net/11420/56225Understanding 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.en1948-718520252667656770American Chemical Societyhttps://creativecommons.org/licenses/by/4.0/Natural Sciences and Mathematics::539: Matter; Molecular Physics; Atomic and Nuclear physics; Radiation; Quantum PhysicsNatural Sciences and Mathematics::541: Physical; TheoreticalTechnology::620: Engineering::620.1: Engineering Mechanics and Materials ScienceJournal Articlehttps://doi.org/10.15480/882.1539210.1021/acs.jpclett.5c0067910.15480/882.15392Journal Article