AndreaBozzo/ceres-open-data-index huggingface dataset:
Synergy of oxygen and water in ceria-catalyzed direct conversion of methane to methanol under continuous flow

The direct conversion of methane to methanol (DCMM) under continuous flow and atmospheric pressure offers notable environmental benefits and industrial promise, but remains a long-standing challenge due to the difficulty of activating CH4 while avoiding over-oxidation of methanol. Here, we demonstrate that pure ceria (CeO2), without any metal promoters, enables gas-phase DCMM with up to 80 % selectivity at 300–350 °C, upon optimization of the H2O/O2 ratio. At 550 °C, methanol and formaldehyde are formed at rates of 24 and 36 μmol g-1 h-1, respectively-both dropping below 1 μmol g-1 h-1 in the absence of O2. Ex situ transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy confirm that CeO2 maintains structural integrity and resists carbon deposition during reaction. Combining kinetic studies, steady-state in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS), and density functional theory (DFT) reveals that hydroxyl groups (OH), generated from water dissociation, play a multifaceted role: they facilitate C–H bond activation, promote methoxy formation, and enhance methanol desorption. In-situ ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) directly reveals the evolution of surface intermediates and shows that co-feeding O2 and H2O suppresses CH3O and CHx accumulation while boosting methanol yield—indicating a rapid intermediate turnover as key to sustained activity. AP-XPS O 1s spectra further highlight that O2 promotes H2O dissociation, regenerating reactive OH groups and maintaining performance at elevated temperature. These findings offer molecular-level insights into how water and oxygen cooperatively tune reactivity, enabling efficient methane-to-methanol conversion on a metal-free oxide catalyst.

Tags: ap-xps, ceo2, dft, in-situ, in-situ-drifts, methane-to-methanol, reaction-mechanism
Enhancing chemoselectivity of on-surface reactions on reconstructed Au(110): the case of a pentalene-bridged polyacene analogue

Polyacene analogues, consisting of short acene segments separated by nonbenzenoid rings, offer intriguing electronic properties and magnetic interactions. Pentalene-bridged polyacenes (PPs), in particular, hold promise for enhancing the electrical conductivity and potential open-shell ground states. However, PPs have remained elusive in solution chemistry due to poor solubility and limited synthetic protocols. In a recent publication,  we report the on-surface synthesis of PPs through the annulation between ortho-xylene groups. Scanning tunneling microscopy and atomic force microscopy reveal that the reconstructed Au(110) surface significantly enhances the chemoselectivity of the annulation process. Scanning tunneling spectroscopy combined with density functional theory suggests that PP exhibits a narrow direct band gap, similar to long acenes. This work demonstrates the potential for band structure engineering in polyacene analogues by incorporating nonbenzenoid rings, paving the way to advancements in organic electronics and spintronics. This record contains computational data supporting the results discussed in the manuscript.

Tags: annulation, dft, hydrocarbons, marvelp4, on-surface-synthesis, scanning-tunneling-microscopy
Electrically driven first-order phase transition of a 2D ionic crystal at the electrode/electrolyte interface

Liquid electrolytes adsorbed at the surface of metallic electrodes display a multitude of structures that can largely differ from the parent bulk system, both in terms of composition and local organization. In particular, the existence of disorder-order or order-order transitions has been increasingly reported in experimental and simulation studies, and the electrode potential identified as the corresponding driving force. The microscopic mechanisms and the stages of the process are, however, poorly understood, and the free energy variation during the transition remains insufficiently characterized. To fill this gap, we investigate the crystallization of the adsorbed layer in a prototypical molten salt-metal interface. We demonstrate that the transition from the disordered to ordered structures proceeds in two stages. Pre-ordering effects are observed across a wide range of potentials, resulting in the formation of a poly-crystalline structure on the electrode surface, before an abrupt ordering transition finally occurs. The pre-ordering displays signature of a continuous transition. On the other hand, finite-size effects analysis proves the first-order character of the transition towards the mono-crystalline state. Upon increasing the system size, a shift in the onset applied voltage is observed, accompanied by a dramatic increase in the free energy barrier. The latter reflects in the interfacial capacitance, which displays a peak that sharpens with increasing system size.

Tags: electrochemical-interface, electrolyte, molecular-dynamics, order-disorder-transition
Absorption lines of F centers in MgO and CaO through time-dependent hybrid-functional theory calculations

We investigate the absorption spectra of the F centers in MgO and CaO using material-specific hybrid functionals combined with time-dependent hybrid-functional theory calculations. Our study accounts for electron-hole interaction, zero-phonon renormalization, and finite-size effects, which are all found to contribute to the achieved accuracy. The spectra of the neutral states solely present absorption lines stemming from internal defect-to-defect transitions without involving conduction band states of the host. At variance, the spectra of the singly positively charged states show two lines, one analogous to those seen in the neutral states and an extra line corresponding to electron excitations from the valence band to the unoccupied defect level in the band gap. In MgO, the three transition energies pertaining to these two charged states are found to coincide, but are spread out in the case of CaO. The agreement with the energies of experimental lines is excellent, indicating that our scheme reaches an accuracy of 0.2 eV or better.

Tags: defect, dft, oxide, time-dependent-dft
A deep learning model for chemical shieldings in molecular organic solids including anisotropy

Nuclear Magnetic Resonance (NMR) chemical shifts are powerful probes of local atomic and electronic structure that can be used to resolve the structures of powdered or amorphous molecular solids. 
Chemical shift driven structure elucidation depends critically on accurate and fast predictions of chemical shieldings, and machine learning (ML) models for shielding predictions are increasingly used as scalable and efficient surrogates for demanding ab initio calculations. However, the prediction accuracies of current ML models still lag behind those of the DFT reference methods they approximate, especially for nuclei such as 13C and 15N. Here, we introduce \shiftmlthree{}, a deep-learning model thatimproves the  accuracy of predictions of isotropic chemical shieldings  in molecular solids, and does so while also predicting the full shielding tensor. 
On experimental benchmark sets, we find root-mean-squared errors with respect to experiment for ShiftML that approach those of DFT reference calculations, with RMSEs of 0.53 ppm for 1H, 2.4 ppm for 13C, and 7.2 ppm for 15N, compared to DFT values of 0.49 ppm, 2.3 ppm, and 5.8 ppm, respectively.

Tags: machine-learning, nmr, snsf
Creep dataset from peer-reviewed literature of nuclear structural materials

The dataset provides records of creep properties for structural materials used in nuclear applications, focusing on the influence of specimen dimensions on time-dependent deformation behavior. It was developed through an extensive literature search of peer-reviewed articles, technical reports, and institutional databases, including contributions from 50 publications and databases. The search targeted studies presenting quantitative creep data for both standard and sub-sized specimens, with detailed information on testing conditions, specimen geometries, and material compositions. The compiled database contains 1,413 creep testing records covering parameters that include alloy type and grade, chemical composition, thermal and mechanical treatment history, irradiation conditions, specimen geometry and dimensions, and measured creep properties. The dataset encompasses material classes such as stainless steels (A709, SS304, SS316), reactor pressure vessel steels (SA533, SA508), nickel-based alloys (IN600, IN617), and zirconium alloys (Zr-2, Zr-3, Zr-4). Experts in materials science reviewed and validated all records, verifying material specifications, treatment conditions, and testing parameters for consistency and accuracy.

Tags: creep-test, nuclear-structural-materials, size-effect, sub-sized-specimens
Understanding the origin of superconducting dome in electron-doped MoS₂ monolayer

We investigate the superconducting properties of molybdenum disulphide (MoS₂) monolayer across a broad doping range, successfully recreating the so far unresolved superconducting dome. Our first-principles findings reveal several dynamically stable phases across the doping-dependent phase diagram. We observe a doping-induced increase in the superconducting transition temperature Tc, followed by a reduction in Tc due to the formation of charge density waves (CDWs), polaronic distortions, and structural transition from the H to the 1T′ phase. Our work reconciles various experimental observations of CDWs in MoS₂ with its doping-dependent superconducting dome structure, which occurs due to the 1×1 H to 2×2 CDW phase transition.

Tags: 2d-materials, charge-density-wave, first-principles, lattice-model, migdal-eliashberg, nonadiabaticity, polarons, prace, superconductivity
Predicting topological entanglement entropy in a Rydberg analog simulator

Predicting the dynamical properties of topological matter is a challenging task, not only in theoretical and experimental settings, but also computationally. Numerical studies are often constrained to studying simplified models and lattices. Here we propose a time-dependent correlated ansatz for the dynamical preparation of a quantum-spin-liquid state on a Rydberg atom simulator. Together with a time-dependent variational Monte Carlo technique, we can faithfully represent the state of the system throughout the entire dynamical preparation protocol. We are able to match not only the physically correct form of the Rydberg atom Hamiltonian but also the relevant lattice topology at system sizes that exceed current experimental capabilities. This approach gives access to global quantities such as the topological entanglement entropy, providing insight into the topological properties of the system. Our results confirm the topological properties of the state during the dynamical preparation protocol, and deepen our understanding of topological entanglement dynamics. We show that, while the simulated state exhibits local properties resembling those of a resonating-valence-bond state, in agreement with experimental observations, it lacks the latter’s characteristic topological entanglement entropy signature irrespective of the degree of adiabaticity of the protocol.

Tags: dynamics, marvelqs, quantum-spin-liquids, topological, variatonal-monte-carlo
Proximity-driven magnetic coupling between an open-shell nanographene and a rare-earth surface alloy

Open-shell nanographenes have attracted significant attention due to their structurally tunable spin ground state. While most characterization has been conducted on weakly interacting substrates such as noble metals, the influence of magnetic surfaces remains largely unexplored. In a recent publication,  we investigate how TbAu2, a rare-earth-element-based surface alloy, affects the magnetic properties of phenalenyl (or [2]triangulene (2T)), the smallest spin-1/2 nanographene. Scanning tunneling spectroscopy (STS) measurements reveal a striking contrast: while 2T on Au(111) exhibits a zero-bias Kondo resonance─a hallmark of a spin-1/2 impurity screened by the conduction electrons of the underlying metal─deposition on TbAu2 induces a symmetric splitting of this feature by approximately 20 mV. This opening is large compared to the few meV splitting induced by externally applied magnetic fields. We attribute this splitting to a strong proximity-induced interaction with the ferromagnetic out-of-plane magnetization of TbAu2. Moreover, our combined experimental and many-body model analysis demonstrates that this interaction is spatially modulated, following the periodicity of the TbAu2 surface superstructure. These findings highlight that TbAu2 serves as a viable platform for stabilizing and characterizing the magnetic properties of spin-1/2 nanographenes and for studying the interactions of more complex π-magnetic materials with magnetic substrates. The record contains data supporting the results presented in the publication

Tags: dftu, marvelp4, open-shell-molecules, proximity-interaction, scanning-tunneling-microscopy, spin
Million-Atom Simulation of the Set Process in Phase
Change Memories at the Real Device Scale

Phase change materials are exploited in several enabling technologies such as storage class memories, neuromorphic devices and memories embedded in microcontrollers. A key functional property for these applications is the fast crystal nucleation and growth in the supercool liquid phase. Over the last decade, atomistic simulations based on density functional theory (DFT) have provided crucial insights on the early stage of this process. These simulations are, however,restricted to a few hundred atoms for at most a few ns. More recently, the scope of the DFT simulations has been greatly extended by leveraging on machine learning techniques. In our paper, we show that the exploitation of a recently devised neural network potential for the prototypical phase change compound Ge2 Sb2Te5 (GST)  allows simulating the crystallization process in a multimillion atom model at the length and time scales of the real memory device. The simulations provide a vivid atomistic picture of the subtle interplay between crystal  nucleation and crystal growth from the crystal/amorphous rim in a model mimicking the operationof the memory in the Wall geometry. Our simulation showes that at realistic conditions of the set operation of the memory in the Wall architecture the crystallization is dominated by growth at the crystal-amorphous interface. Moreover, the simulations have allowed quantifying the distribution of point defects that controls electronic transport, in a very large crystallite grown at the real conditions of the set process of the device.

Tags: crystallization, device-scale, electronic-memories, machine-learning-potentials, phase-change-materials
Magnon-phonon interactions from first principles

In this paper, we show many-body calculations of magnon-phonon (mag-ph) coupling based on the ab initio Bethe-Salpeter equation. We derive expressions for mag-ph coupling matrices and compute them in 2D ferromagnets, focusing on hydrogenated graphene and monolayer CrI3. Our analysis shows that electron-phonon (e-ph) and mag-ph interactions differ significantly, where modes with weak e-ph coupling can exhibit strong mag-ph coupling (and vice versa), and reveals which phonon modes couple more strongly with magnons. In both materials studied here, the inelastic magnon relaxation times decrease abruptly above the threshold for emission of strongly coupled phonons, revealing a low-energy window where magnons are long-lived. Averaging over this window, we compute the temperature-dependent magnon mean-free path, a key figure of merit for spintronics, entirely from first principles. The theory and computational tools shown in this work enable studies of magnon interactions, scattering, and dynamics in generic materials, advancing the design of magnetic systems and magnon- and spin-based devices.

This archive include the necessary inputs for DFT, DFPT in Quantum Espresso, and GW-BSE in Yambo code. Since the routine for magnon-phonon coupling is not published, we provided the raw data files used for the figures in our paper as the reference.

Tags: bethe-salpeter-equation, first-principles, magnon-phonon-coupling
Electron-phonon coupling in magnetic materials using the local spin density approximation

Magnetic materials are crucial for manipulating electron spin and magnetic fields, enabling applications in data storage, spintronics, charge transport, and energy conversion, while also providing insight into fundamental quantum phenomena. In numerous applications, the interaction between electrons and lattice vibrations, known as electron-phonon coupling, can be of significant importance. In that regard, we extend the EPW package to be able to interpolate the electron-phonon matrix elements combining perturbation theory and maximally localized Wannier functions. This advance allows to use dense momentum grids at a reasonable computational cost when computing electron-phonon-related quantities and physical properties. We validate our implementation considering ferromagnetic iron and nickel where we explore the absence of phonon-driven superconductivity, finding that superconductivity is intrinsically suppressed. Furthermore, we evaluate the carrier resistivity at finite temperatures for both systems, considering the role of magnetism in carrier transport. Our findings indicate that in the case of Fe, the primary contributor to resistivity is electron-phonon scattering. In contrast, for Ni, electron-phonon scattering constitutes less than one-third of the resistivity, underscoring a fundamental difference in the transport properties of the two systems.

Tags: electron-phonon-coupling, magnetism, wannier-functions
Thermoresponsive copolymer microgels synthesized via single-step precipitation polymerization: random or block structure?

The inner structure of polymeric microgels critically influences their responsiveness and potential applications, yet remaining challenging to resolve at molecular resolution. In this work, a structural characterization of thermoresponsive copolymer microgels is provided by integrating small-angle neutron scattering (SANS), dynamic light scattering (DLS), and nuclear magnetic resonance (NMR) measurements with multi-scale simulations. Specifically, Poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide), P(NIPAM-co-NIPMAM), copolymer microgels, in which a random monomer distribution is conventionally assumed, are considered. By synthesizing different samples, including isotopically labeled microgels via selective deuteration, the microgels swelling behavior is probed and distinct polymer-specific signatures are revealed. To elucidate their internal distribution, monomer-resolved microgel simulations are performed across different copolymer models. A direct comparison between experimental and numerical form factors provides evidence of preferential organization into block structures, challenging the prevailing view of random distribution. 13C-NMR experiments confirm NIPAM-rich blocks and atomistic simulations link this unexpected block-like architecture to distinct local hydrogen-bonding patterns. This integrated approach provides the first direct evidence of preferential block formation in P(NIPAM-co-NIPMAM) microgels. Beyond this system, these results establish a generalizable strategy for unveiling hidden structural order in copolymer microgels, offering new strategies to tailor their design and to enhance control of material responsivity.

Tags: copolymerization, microgels, molecular-modeling, nmr-spectroscopy, selective-neutron-scattering
Effect of the OH functionalization on the catalytic activity of single-atom catalyst

The existence of the hydroxyl ligand on a single- atom catalyst embedded in graphene, especially Fe(OH)−N4−C is suggested to improve the oxygen reduction reaction (ORR) from the pristine Fe−N4−C. However, the theoretical electrocatalytic activity of the ORR process is shown to be highly dependent on the electrolyte solution and the applied electrode potential. Herein, we performed the constant-potential simulation and microkinetic modeling to investigate the mechanism of ORR on well studied Fe(OH)−N4−C and Co(OH)−N4−C catalysts and compared to the pristine ones, using density functional theory (DFT) calculation combined with the effective screening medium method and the reference interaction site model (ESM-RISM). It was found that the Fe(OH)−N4−C and Co(OH)−N4−C have comparable ORR activities to Fe−N4−C and Co−N4−C, and the calculated limiting potentials and half-wave potentials agree with the experimental values, in contrast to the results obtained using the constant-charge method (i.e., under the neutral condition) regardless of consideration of the solvation effect.

Tags: density-functional-theory, implicit-solvation-model, oxygen-reduction-reaction, single-atom-catalyst
Phonon-limited carrier transport in the Weyl semimetal TaAs

Topological Weyl semimetals represent a novel class of quantum materials that exhibit remarkable properties arising from their unique electronic structure. In this work, we employ state-of-the-art ab initio methods to investigate the role of the electron-phonon interactions on the charge transport properties of TaAs. Our calculations of the temperature-dependent electrical conductivity with the iterative Boltzmann transport equation show excellent agreement with experimental measurements above 100 K. Extending the analysis to doped systems, we demonstrate that even small shifts in the Fermi level can lead to substantial changes in conductivity, driven by the complex topology of the Fermi surface. In particular, modifications in Fermi surface nesting emerge as a key factor influencing scattering processes and carrier lifetimes. These findings offer critical insights into the microscopic mechanisms that govern transport in TaAs and highlight the sensitivity of Weyl semimetals to doping and carrier dynamics.
This record includes (i) the code and input files used for the calculations, and (ii) the data and plotting scripts used to generate the figures in the paper.

Tags: electron-phonon-coupling, first-principles, transport, weyl-semimetals
Precision verification results data for ABACUS@PW|PseudoDojo-v0.4

Density functional theory calculations have been a pillar of computational materials science in the past two decades, and the recent development of AI and data-driven methods has reiterated their importance. ABACUS (Atomic-orbital Based Ab-initio Computation at USTC) is an open-source density functional theory code that supports both plane-wave and numerical atomic orbital basis sets. It is designed as a versatile platform integrating various electronic structure methods and is particularly well-suited for deep-learning-assisted materials simulations. The accuracy of a density functional theory code is crucial for its wide deployment. In this work, we use the verification protocol established by E. Bosoni et al. [Nat. Rev. Phys. 6, 45-58 (2024)] based on the AiiDA common workflows framework to validate the precision of ABACUS by comparing its results with previously generated all-electron benchmarks. Our results show that, using consistent pseudopotentials and comparable calculation settings, ABACUS yields highly consistent results compared to other established codes such as QE, Abinit, and CASTEP. This entry contains all the data, calculations, and scripts required to reproduce the results.

Tags: automation, dft, equation-of-state, pseudopotentials, verification