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We explore the role of molten nitrate interfaces on MgO surface treatment for improving the reversibility of thermochemical energy storage via sorption and desorption of water or CO2. Our molecular dynamics simulations focus on melts of LiNO3, NaNO3, KNO3, and the triple eutectic mixture Li0.38Na0.18K0.44NO3 on the surface of MgO to provide atomic scale details of adsorbed layers and to rationalize interface energies. On this basis, a thermodynamic model is elaborated to characterize the effect of nitrate melts on the dehydration of Mg(OH)2 and to quantitatively explain the difference in dehydration temperatures of intact and LiNO3-doped Mg(OH)2.

Solid catalysts with ionic liquid layers (SCILLs) are heterogeneous catalysts which benefit significantly in terms of selectivity from a thin coating of an ionic liquid (IL). In the present work, we study the interaction of CO with a Pd model SCILL consisting of a 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide ([C4C1Pyr][NTf2]) film deposited on Pd(111). We investigate the CO permeability and stability of the IL film via pressure modulation experiments by infrared reflection absorption spectroscopy (IRAS) in ultrahigh vacuum (UHV) and at ambient pressure conditions by time-resolved, temperature-programmed, and polarization-modulated (PM) IRAS experiments. In addition, we performed molecular dynamics (MD) simulations to identify adsorption motifs, their abundance, and the influence of CO. We find a strongly bound IL wetting monolayer (ML) and a potentially dewetting multilayer. Molecular reorientation of the IL at the interface and multilayer dewetting allow for the accumulation of CO at the metal/IL interface. Our results confirm that co-adsorption of CO changes the molecular structure of the IL wetting layer which confirms the importance to study model SCILL systems under in situ conditions. Graphical abstract

Nano-/microplastics (NP) is a human-made emerging contaminant with worldwide occurrence. The small size (below one micrometer), the different chemical nature and the persistence make NP to potential hazards with suspect probability of tissue penetration and inflammation or as accumulator for toxins. A strategy to stop the spill of novel NP is the remediation from waste water or rivers as prominent distributors. We have developed core–shell superparamagnetic iron oxide nanoparticles (SPIONs) that attract NP and glue them to larger agglomerates which then can be removed from water by applying an external magnetic field. The shell molecules provide two interaction motifs towards NP. The tuned surface potential of the functionalized SPIONs attract complementary charged NP efficiently and the n-alkyl chain is dedicated to preferential interaction towards organic NP rather than inorganic particles. Structural analytics and molecular dynamics simulation support the proposed concept. Systematic remediation experiments with different NP (chemical structures, sizes and mixtures), from different waters – including river water – and with different SPION core materials indicate a universal validity of the concept, with best remediation performance for mixed NP. We suggest a method for broadband remediation of various NP with simple materials and processes, which both have the potential to be up-scaled.

In this study, we unravel the atomic structure of a covalent resin near boundaries such as surfaces and composite constituents. For this, a molecular simulation analysis of epoxy resin hardening under various boundary conditions was performed. On the atomic level of detail, molecular dynamics simulations were employed to study crosslinking reactions and self-organization of the polymer network within nm scale slab models. The resulting structures were then coarsened into a graph theoretical description for connectivity analysis of the nodes and combined with characterization of the node-to-node vector orientation. On this basis, we show that the local bonding of epoxy resins near interfaces tends to avoid under-coordinated linker sites. For both epoxy–vacuum surface models and epoxy–silica/epoxy cellulose interfaces, we find almost fully cured polymer networks. These feature a local increase in network linking lateral to the surface/interface, rather than the dangling of unreacted epoxy groups. Consequently, interface tension is low (as compared to the work of separating bulk epoxy), and the reactivity of the resin surface appears negligible.

Small‐molecular‐weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which these additives regulate stability and composition of both CaCO3 solutions and solid ACC. Potent antiscalants inhibit ACC precipitation by interacting with prenucleation clusters (PNCs); they specifically trigger and integrate into PNCs or feed PNC growth actively. Only PNC‐interacting additives are traceable in ACC, considerably stabilizing it against crystallization. The selective incorporation of potent additives in PNCs is a reliable chemical label that provides conclusive chemical evidence that ACC is a molecular PNC‐derived precipitate. Our results reveal additive‐cluster interactions beyond established mechanistic conceptions. They reassess the role of small‐MW molecules in crystallization and biomineralization while breaking grounds for new sustainable antiscalants.

We model bond formation and dissociation processes in thermosetting polymer networks from molecular dynamics simulations. For this, a coarsened molecular mechanics model is derived from quantum calculations to provide effective interaction potentials that enable million-atoms scale simulations. The importance of bond (re)organization is demonstrated for (i) simulating epoxy resin formation─for which our approach leads to realistic network models which can now account for degrees of curing up to 98%. Moreover, (ii) we elucidate the competition of bond dissociation and bond reformation during plastic deformation and fracture. On this basis, we rationalize the molecular mechanisms that account for the irreversible nature of damaging epoxy polymers by mechanical load.

For over two decades, NaCl nucleation from a supersaturated aqueous solution has been predicted to occur via a two-step nucleation (TSN) mechanism, i.e., two sequential events, the formation of locally dense liquid regions followed by structural ordering. However, the formation of dense liquid regions in the very early stage of TSN has never been experimentally observed. By using a state-of-the-art technique, a combination of electrostatic levitation (ESL) and in situ synchrotron X-ray and Raman scatterings, we find experimental evidence that indicates the formation of dense liquid regions in NaCl bulk solution at an unprecedentedly high level of supersaturation (S = 2.31). As supersaturation increases, evolution of ion clusters leads to chemical ordering, but no topological ordering, which is a precursor for forming the dense disordered regions of ion clusters at the early stage of TSN. Moreover, as the ion clusters proceed to evolve under highly supersaturated conditions, we observe the breakage of the water hydration structure indicating the stability limit of the dense liquid regions, and thus leading to nucleation. The evolution of solute clusters and breakage of hydration in highly supersaturated NaCl bulk solution will provide new insights into the detailed mechanism of TSN for many other aqueous solutions., This work provides evidence for two-step nucleation in highly supersaturated bulk NaCl solution, using electrostatic levitation combined with Raman/X-ray scatterings.

In this study, we report on hexa-peri-hexabenzocoronenes (HBCs) as representative models for nanographenes. To this end, we synthesized a family of functionalized HBCs and investigated the impact of the substituents on the π-extended systems of the HBCs. DFT and TD-DFT calculations suggested a charge transfer character, which intensified as the electron density withdrawing effects of the substituents (–M-effect) increased. Unambiguous corroboration of the charge transfer character in the case of NO2-substituents was realized via steady-state absorption and fluorescence experiments, which focused on the dependencies on the solvent polarity and temperature featuring. Going beyond HBCs with NO2-substituents, time-correlated single photon counting, and femtosecond and nanosecond transient absorption spectroscopy unveiled long-lived singlet and triplet excited states. As a complement, we performed electrochemical and spectroelectrochemical measurements. These measurements were carried out to shed light onto the nature of the functionalized HBCs as electron acceptors and/or donors, on the one hand, and their corresponding spectroscopic signatures, on the other hand. All of the aforementioned information enabled intermolecular charge separation assays with, for example, suitable electron acceptors by steady-state and time-resolved spectroscopy.

Strontium substituted apatite-(CaF)-gelatin composites have been synthesized within a gelatin gel using the double diffusion technique. All experimental parameters were kept constant while systemat...

Solution-based processing of photovoltaic materials has important advantages, including lower overall costs and easier upscaling of fabrication, where the solvents play an essential role. Antisolvent crystallization technique is often applied to achieve high-quality perovskite materials. However, the basic chemistry of the solvent-antisolvent crystallization is still not well understood. Besides, common antisolvents are toxic, and their number is limited. In this work, a novel robot-based method was used to screen the efficient antisolvents for different solvent-perovskite systems. 336 combinations of perovskite-solvent-antisolvent could be prepared and characterized by the integrated robotic platform in 2 days. In addition, we provided a detailed working mechanism of the solvent-antisolvent crystallization approach. Furthermore, hundreds of potential antisolvents were proposed based on high-throughput screening and simulation. Verification tests match well with theory, and all reported antisolvents used for photovoltaic device optimizations are within our predicted range of the Hansen space, indicating that the predictions are reliable. In terms of solution-processed lead halide perovskite optoelectrical materials, suitable antisolvent is essential for the crystallization and properties of final products. Conventional experiments of antisolvent selections are based on the manual time-consuming trial-error methods, which cannot meet today's increasing demands. In this work, a robot-based method was used to screen the antisolvents for different solvent-perovskite systems in a high-throughput manner to study the influence of interactions among the solvent molecules, cations, metal-halides, and antisolvents, to build an informative database, and to reveal the working mechanism and selection criteria of antisolvents. Besides, simulations based on the screening results provide hundreds of potential antisolvents. Corresponding verification tests evidenced that our predictions are reliable and vital for designing future efficient mixed solvent systems for the fabrication of perovskite optoelectrical materials. A robotic platform is adopted to conduct a comprehensive solvent engineering for making lead halide perovskites in a high-throughput manner. Deeper insights into the working mechanisms and selection criteria of antisolvents are investigated and summarized. In addition, a reliable antisolvent database is established, and verification tests match well with the theory. Furthermore, our work provides significant guidance for designing functional and environment-friendly mixed solvent systems to fabricate high-quality perovskite materials or devices.

We present atomic scale models of differently shaped silica surfaces loaded by gemcitabine and ibuprofene molecules. Despite the dissimilar nature of the drug molecules, their association to silica carriers shows quite similar characteristics. We identify a well-defined contact layer that is stabilized by silica-molecule salt-bridges/hydrogen bonding in parallel to interactions among the drug molecules. Additional loading of the carriers leads to rough films with dynamically evolving asperities rather than layer-by-layer ordering. To elucidate the role of differently shaped silica surfaces, we compared planar slab models and spherical nanoparticles as 2 limiting cases. Despite the strong difference in the curvature of the silica surfaces, our molecular dynamics simulations show only small changes of the unloading characteristics. This suggests that the design of different pore shapes in mesoporous silica–based drug carriers mainly affects the migration kinetics rather than the energetics of drug loading and release.

Solutions of gallium trihalides GaX 3 (X=F, Cl, Br, I) and their ammoniates in liquid ammonia were studied at ambient temperature under autogenous pressure by multinuclear (71Ga, 35Cl, 81Br) NMR spectroscopy. To unravel the role of pH, the analyses were done both in absence and in presence of ammonium halides, which are employed as mineralizers during ammonoacidic gallium nitride crystal growth. While gallium trifluoride and its ammoniate were found to be too sparingly soluble to give rise to a NMR signal, the spectra of solutions of the heavier halides reveal the presence of a single gallium‐containing species in all cases. DFT calculations and molecular dynamics simulations suggest the identification of this species as consisting of a [Ga(NH3)6]3+ cation and up to six surrounding halide anions, resulting in an overall trend towards negative complex charge. Quantitative 71Ga NMR studies on saturated solutions of GaCl3 containing various amounts of additional NH4Cl revealed a near linear increase of GaCl3 solubility with mineralizer concentration of about 0.023 mol GaCl3 per mol NH4Cl at room temperature. These findings reflect the importance of Coulombic shielding for the inhibition of oligomerization and precipitation processes and help to rationalize both the low solubility of gallium halides in neutral ammonia solution and, in turn, the proliferating effect of the mineralizer during ammonoacidic gallium nitride formation., Materials synthesis: A combination of solution NMR in liquid ammonia with quantum mechanical and molecular modelling allows identifying the dissolved species and their mineralizer concentration dependent solubility in ammonoacidic solutions with relevance for GaN crystal growth (see figure).

Indicators for H2 are crucial to ensure safety standards in a green hydrogen economy. Herein, the authors report micron‐scaled indicator supraparticles for real‐time monitoring and irreversible recording of H2 gas via a rapid eye‐readable two‐step color change. They are produced via spray‐drying SiO2 nanoparticles, AuPd nanoparticles, and indicator‐dye resazurin. The resulting gas‐accessible mesoporous supraparticle framework absorbs water from humid atmospheres to create a three‐phase‐system. In the presence of H2, the color of the supraparticle switches first irreversibly from purple to pink and further reversibly to a colorless state. In situ infrared spectroscopy measurements indicate that this color change originates from the (ir)reversible H2‐induced reduction of resazurin to resorufin and hydroresorufin. Further infrared spectroscopic measurements and molecular dynamics simulations elucidate that key to achieve this functionality is an established three‐phase‐system within the supraparticles, granting molecular mobility of resazurin. Water acts as transport medium to carry resazurin molecules towards the catalytically active AuPd nanoparticles. The advantages of the supraparticles are their small dimensions, affordable and scalable production, fast response times, straightforward bare‐eye detection, and the possibility of simultaneously monitoring H2 exposure in real‐time and ex post. Therefore, H2 indicator supraparticles are an attractive safety additive for leakage detection and localization in a H2 economy.

We outline comparably simple molecular simulation techniques to elucidate the interactions that determine the polymorphism of carbamazepine. Starting from the established GAFF molecular mechanics model, only a small series of tailor-made improvements is needed to tackle the subtle differences in the interaction energies of polymorphs I - IV. On this basis, molecular dynamics simulations provide melting enthalpies at1 kcal/mol accuracy (0.2 kcal/mol for forms I-III) as compared to the experiment. Yet, the predicted stability ranking of IIIIIIIV only partially reproduces the experimentally observed IIIIIVII series. Despite this limitation, we demonstrate how insights from molecular simulation offer the elucidation of possible factors for polymorph control. Apart from characterizing bulk crystals, we outline the evaluation of size-dependent profiles of crystallite formation energy. Contrasting the contributions of bulk, surface and edge terms to the formation energy of nano-scale precipitates, we suggest a multi-step nucleation mechanism leading from amorphous aggregates to crystallites. We argue that carbamazepine aggregates of less than ∼100 molecules adopt a spherical shape to minimize edge/surface energy - overcompensating the loss in bulk energy inherent to non-crystalline ordering in the inner core. In turn, for large crystallites polymorph form III is preferred, whilst suitable spatial confinement to crystallites of 100-500 carbamazepine molecules appears to promote form II.

A key requisite to characterizing GaN precipitation from ammonia solution from molecular simulations is the availability of reliable molecular mechanics models for the interactions of gallium ions with NH

We present the convenient synthesis and characterization of the new ternary thiostannate Na

We provide tailor-made GAFF2-type interaction potentials for modeling ammonium and amide ions in ammonia. Based on harmonic approximation of intra-molecular bond stretching and bending, our force fields nicely reproduce the vibrational modes of NH

Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which additives regulate stability and composition of both CaCO3 solutions and solid ACC. Potent antiscalants inhibit ACC precipitation by interacting with prenucleation clusters (PNC); they specifically trigger and integrate into PNCs or feed PNC growth. Only PNC-interacting additives are traceable in ACC, considerably stabilizing it against crystallization. The selective incorporation of potent additives in PNCs is a reliable chemical label that provides conclusive chemical evidence that ACC is a molecular precipitate derived PNCs. Our results reveal additive-cluster interactions beyond established mechanistic conceptions. They reassess the role of small-MW molecules in crystallization and biomineralization, while breaking grounds for new sustainable antiscalants.

Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which additives regulate stability and composition of solid ACC and CaCO3 solutions simultaneously. Effective precipitation inhibition arises from pronounced interaction of additives with prenucleation clusters (PNC). Potent antiscalants specifically trigger and integrate into PNCs. Only PNC-interacting additives are traceable in solid ACC, considerably stabilizing ACC against transformation. This co-precipitation specificity facilitates a chemical labeling of PNCs, evidencing ACC as a molecular precipitate of PNCs. Our results reveal additive-cluster interactions that operate beyond established mechanistic conceptions and thus reassess the role of small-MW molecules in crystallization and especially in biomineralization while breaking grounds for new sustainable antiscalants.

We outline molecular dynamics simulations of electrode–ionic liquid interfaces with explicit consideration of electronic polarization effects. For this, conventional molecular mechanics are extende...

This molecular dynamics simulations study elucidates how water diffusion in MgCl2·nH2O (n=4 and 6) is facilitated by defects and dopants. Both the impact of a single vacancy (one water molecule was removed) and an interstitial (one water molecule was added) on long range water motion has been investigated. Spontaneous vacancy-interstitial pair defect formation was not observed, which is in line with the predicted high energy costs for defect formation: 150 and 200 kJ/mol for the tetrahydrate and hexahydrate, respectively. The vacancy defects did not show long range mobility, which we relate to the strong bonding of water in the coordination shell of the Mg-ion that prevents water molecules from shifting to neighbouring magnesium ions. On the contrary, the addition of an extra water molecule, facilitates long range motion, which was found as a sequence of hopping events. The interstitial motion is anisotropic in both tetrahydrate and hexahydrate crystals, as interstitials preferentially reside at locations of unfavourable Cl-Cl interactions. Strikingly, Mg ↔ Ca substitutional defects neither increase the mobility of vacancies nor facilitates interstitial motion in the MgCl2 lattice. While Ca dopants slightly facilitate vacancy formation, it also stabilizes interstitial water molecules by incorporating these molecules in its coordination shell. As a consequence, the interstitial becomes trapped and loses its mobility. Therefore, Ca dopants will not increase the hydration/dehydration kinetics of MgCl2 hydrates and cannot be used to boost the power output of MgCl2-based heat storage devices.

The ability of a series of bridged triarylamines, so‐called N‐heterotriangulenes, to form multilayer‐type 2D‐extended films via a solution‐based processing method was examined using complementary microscopic techniques. We found that the long‐range order, crystallinity, and layer thickness decisively depend on the nature of the substituents attached to the polycyclic backbone. Owing to their flat core unit, compounds exhibiting a carbonyl unit at the bridge position provide a superior building block as compared to thioketone‐bridged derivatives. In addition, nature and length of the peripheral substituents affect the orientation of the aromatic core unit within highly crystalline films. Hence, our results stress the significance of a suitable molecular framework and provide deeper understanding of structure formation in 2D‐confined surroundings for such compounds., Towards layered organic electronics: The in‐plane and out‐of‐plane alignment as well as the morphology of solution‐processed N‐heterotriangulene films is found to depend on the nature of the bridge and peripheral substituents attached to the core unit. Spectromicroscopic characterization allows for the understanding of structure formation under 2D‐confined conditions and illustrates the significance of a customizable molecular framework for well‐defined layered systems.

Here, we approach the issue of ACC ultrastructure by applying a method for determining atomically resolved structures of amorphous materials using Monte Carlo simulations constrained by both X-ray and neutron scattering data. This structural analysis approach allows us to develop a detailed model for ACC at the atomic level. Our findings reveal that synthetic ACC, rapidly precipitated at high pH, consists of two-nanometer sized units containing a high degree of near range order similar to partially disordered nano-crystals. Small-angle scattering analyses show a multi-scale hierarchical organisation of the structure, supportive of a multi-step colloid self-assembly process. Computer simulations and high-resolution transmission electron microscopy show that the mesostructure of ACC resembles that of a glassy gel with crystalline material in domains. Our findings support the formation of ACC by a nanoparticle aggregation process that likely starts from prenucleation clusters in solution.

Epoxy resin plasticity and damage was studied from molecular dynamic simulations and interpreted by the help of constitutive modelling. For the latter, we suggested a physically motivated approach that aims at interpolating two well-defined limiting cases; namely, pulling at the vanishing strain rate and very rapid deformation; here, taken as 50% of the speed of sound of the material. In turn, to consider 0.1–10-m/s-scale deformation rates, we employed a simple relaxation model featuring exponential stress decay with a relaxation time of 1.5 ns. As benchmarks, deformation and strain reversal runs were performed by molecular dynamic simulations using two different strain rates. Our analyses show the importance of molecular rearrangements within the epoxy network loops for rationalizing the strain-rate dependence of plasticity and residual stress upon strain reversal. To this end, our constitutive model reasonably reproduced experimental data of elastic and visco-elastic epoxy deformation, along with the maximum stress experienced before fracturing. Moreover, we show the importance of introducing damage elements for mimicking the mechanical behavior of epoxy resins.

Classical nucleation theory (CNT), which was established about 90 years ago, represents the most commonly used theory in describing nucleation processes. For a fluid-to-solid phase transition, CNT states that the solutes in a supersaturated solution reversibly form small clusters. Once a cluster reaches its critical size, it becomes thermodynamically stable and is favored for further growth. One of the most important assumptions of CNT is that the nucleation process is described by one reaction coordinate and all order parameters proceed simultaneously. Recent studies in experiments, computer simulations, and theory have revealed nonclassical features in the early stage of nucleation. In particular, the decoupling of order parameters involved during a fluid-to-solid transition leads to the so-called two-step nucleation mechanism, in which a metastable intermediate phase (MIP) exists in parallel to the initial supersaturated solution and the final crystals. These MIPs can be high-density liquid phases, mesoscopic clusters, or preordered states. In this Special Issue, we focus on the role of the various MIPs in the early stage of crystal nucleation of organic materials, metals and alloys, aqueous solutions, minerals, colloids, and proteins, and thus on various scenarios of nonclassical pathways of crystallization, F.Z. and D.Z. acknowledge financial support of deutsche Forschungsgemeinschaft.

Ab-initio based benchmarking and improvements of molecular mechanics models for organic friction modifier (OFM) additives used in lubricants are presented. We found the generalized amber force field (GAFF2) appears well suited to model oil-steel interfaces moderated by fatty acids. However, explicit refinements are needed for describing the interactions of fatty acid glycerol esters with steel surfaces and were thus implemented into our OilF force field suite. Apart from analyzing single OFM molecule association to steel, we present a systematic scheme for elucidating the association of additive films to oil-hematite interfaces from molecular dynamics simulations. On this basis, ‘saturated’ interface models of densely packed OFMs are suggested.

Molecular Simulations are increasingly entering the realm of materials syntheses. While pioneering studies were bound to simple models which could only address selected aspects of ‘real chemistry’ in the lab, recent advances in simulation methodology and computing hardware indeed paved the way to also modelling complex systems. Yet, we are hardly more than at the beginning of establishing molecular simulations as a routine tool for guiding syntheses. In the present contribution, we discuss the progress that has been made to understand ammonothermal syntheses of nitrides. This encompasses molecular dynamics simulations based on non-reactive force-fields—such as studies of liquid ammonia as a solvent, and its supercritical nature at high temperature and pressure. Moreover, we report on recent work on quantum and hybrid quantum/classical approaches for modelling the auto-protolysis of ammonia and ammonia protolyses in the course of metal ion solvation. This forms a basis for rationalizing the association of ion aggregates, size-induced proton transfer and the self-organization of amides, imides and nitrides from molecular simulations.

We present a quantum mechanical / molecular mechanics (QM/MM) to tackle chemical reactions with substantial molecular reorganization. For this, molecular dynamics simulations with smoothly switched interaction models are used to suggest suitable product states, whilst a Monte Carlo algorithm is employed to assess the reaction likeliness subject to energetic feasibility. As a demonstrator, we study the cross-linking of bisphenol F diglycidyl ether (BFDGE) and 4,6-diethyl-2-methylbenzene-1,3-diamine (DETDA). The modeling of epoxy curing was supplemented by Differential Scanning Calorimetry (DSC) measurements, which confirms the degrees of cross-linking as a function of curing temperature. Likewise, the heat of formation and the mechanical properties of the resulting thermosetting polymer are found to be in good agreement with previous experiments., To be published in ACS Macromolecules

The mechanism behind the stability of organic nanoparticles prepared by liquid antisolvent (LAS) precipitation without a specific stabilizing agent is poorly understood. In this work, we propose that the organic solvent used in the LAS process rapidly forms a molecular stabilizing layer at the interface of the nanoparticles with the aqueous dispersion medium. To confirm this hypothesis, n-octadecyltrichlorosilane (OTS)-functionalized silicon wafers in contact with water-solvent mixtures were used as a flat model system mimicking the solid-liquid interface of the organic nanoparticles. We studied the equilibrium structure of the interface by X-ray reflectometry (XRR) for water-solvent mixtures (methanol, ethanol, 1-propanol, 2-propanol, acetone, and tetrahydrofuran). The formation of an organic solvent-rich layer at the solid-liquid interface was observed. The layer thickness increases with the organic solvent concentration and correlates with the polar and hydrogen bond fraction of Hansen solubility parameters. We developed a self-consistent adsorption model via complementing adsorption isotherms obtained from XRR data with molecular dynamics simulations.