Atomic Model Research Articles

Platinum-based catalysts for oxygen reduction reaction simulated with a quantum computer

Hydrogen has emerged as a promising energy source for low-carbon and sustainable mobility purposes. However, its applications are still limited by modest conversion efficiency in the electrocatalytic oxygen reduction reaction (ORR) within fuel cells. The complex nature of the ORR and the presence of strong electronic correlations present challenges to atomistic modelling using classical computers. This scenario opens new avenues for the implementation of novel quantum computing workflows. Here, we present a state-of-the-art study that combines classical and quantum computational approaches to investigate ORR on platinum-based surfaces. Our research demonstrates, for the first time, the feasibility of implementing this workflow on the H1-series trapped-ion quantum computer and identify the challenges of the quantum chemistry modelling of this reaction. The results highlight the great potentiality of quantum computers in solving notoriously difficult systems with strongly correlated electronic structures and suggest platinum/cobalt as ideal candidate for showcasing quantum advantage in future applications.

Phosphorus-based heterojunction tunnel field-effect transistors: from atomic insights to circuit renovations.

Tunnel field-effect transistors (TFETs) are gaining interest for low-power applications, but challenges like poor drive current, delayed saturation, and ambipolarity can hinder their performance. This work proposes a dopingless heterojunction TFET (DL-HTDET) utilizing advanced materials, all based on phosphorus, to address these issues. Our approach involves a comprehensive and accurate analysis of the DL-HTDET's behavior. It employs a hybrid simulation technique integrating atomistic modeling, device simulation, and circuit design. For the first time, we use density functional theory to compute the electrical parameters of a two-dimensional material, 10-layer black phosphorus, configured in the armchair direction as the source region. InP serves as the pocket, while AlP, with its high bandgap, acts as the drain region to suppress ambipolarity. Key parameters, including bandgap, effective mass, mobility, static dielectric constant, and electron affinity, are utilized to simulate the device characteristics. Three mechanisms are considered in the device design: interband tunneling, intraband tunneling, and thermionic emission. The effect of pocket length (Lpocket) on performance is studied, and the impact of different types of interface trap charges, ranging from low to high density, is considered, and the optimized device demonstrates good durability. Additionally, the gate leakage current, which is crucial for static power consumption, is taken into account. The DC and analog/radio frequency performance of the device are evaluated. The optimized DL-HTDET achieves an ON-state current of 125 μA μm-1, a current switching ratio of 1016, an average subthreshold swing of 5.10 mV dec-1, and a transconductance of 1.47 mS μm-1. A 7T SRAM cell is implemented, demonstrating high noise margins, low delay, and ultra-low power consumption. These achievements underscore the potential of the proposed device for high-speed, ultralow power applications.

Continuum-Particle Coupling for Polymer Simulations.

We report a concurrent hybrid multiscale simulation method, in which a particle domain is coupled with a surrounding continuum domain. The particle domain consists of a coarse-grained model of poly(lactic acid) and the continuum domain is treated using the finite element method. The coarse-grained model is derived from an atomistic model, using the iterative Boltzmann inversion scheme. The particle- and the finite element-domains overlap in a bridging domain through anchor points. In this coupling, the information passes back and forth between the high- and the low-resolution domains, effectively bridging the gap between the nano and macro-scales. This scheme is employed to simulate the coupled particle-continuum domains under both stochastic and semistochastic boundary conditions. While the anchor points keep the volume of the particle domain fixed in the former case, there is no anchor point in the planes normal to the periodic direction, in the latter case. The stress-strain behavior of polymer under both stochastic and semistochastic boundary conditions is investigated and the results are compared with those calculated from pure finite element reference simulations. Furthermore, the stress-strain relationship for the coupled system under the semistochastic boundary conditions is examined under plane stress and plane strain conditions, and the results are compared with those of pure finite element reference simulations. The hybrid particle-continuum method reproduces the pure finite element simulation results well.

Enhanced Giant Magnetoresistance in Heusler Alloy (Co2FeSi/Ag)N Multilayers for Read Sensor applications

Abstract We theoretically investigate the spin transport behavior of multilayer (Co2FeSi/Ag)N structure for the application of next-generation read sensor in hard disk drive. To demonstrate the potential of Heusler alloy-based current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) device, we employ the atomistic model coupled with the spin accumulation model including the effect of diffuse interface. The dynamic of magnetization is observed by the atomistic model and the calculation of magnetoresistance (MR) and MR ratio of the magnetic structure can be achieved by the spin accumulation model enabling us investigate the spin transport behavior within the structure. The MR value can be directly calculated from the gradient of spin accumulation and spin current. The effect of injected current density is first investigated. It is found that increasing current density results in high MR ratio. Subsequently, to achieve high performance reader, the number of coupled layers (N) is varied up to 16 to study its effect on the MR ratio. The calculated results indicate that increasing the number of layers N gives rise to the enhancement of the resistance change and MR ratio. At the critical point N=5, further increasing N does not affect the MR ratio, which remains relatively unchanged. Interestingly, the MR ratio is doubled for N>5 compared to N=1. Our results show the possibility to enhance the performance of multilayer CPP-GMR device.

Atomic Memory Model

Memory leaks and buffer overruns are among the most common erroneous conditions in computer systems. They are also among the most tedious, difficult and time consuming to detect, identify, locate, and resolve. Both Microsoft and Google independently report that memory safety issues cause 70% of all security vulnerabilities [10]. The Atomic Memory Model provides a mechanism for resolving these types of errors. Simultaneously, it makes the software architecture more robust and elegant by enforcing a code hierarchy regarding the memory use, as well as allowing for innate memory abstraction that matches the application semantics. The model also significantly increases the speed of the software development by relieving developers from detailed memory management.

Architecture of the Sap S-layer of Bacillus anthracis revealed by integrative structural biology

Bacillus anthracis is a spore-forming gram-positive bacterium responsible for anthrax, an infectious disease with a high mortality rate and a target of concern due to bioterrorism and long-term site contamination. The entire surface of vegetative cells in exponential or stationary growth phase is covered in proteinaceous arrays called S-layers, composed of Sap or EA1 protein, respectively. The Sap S-layer represents an important virulence factor and cell envelope support structure whose paracrystalline nature is essential for its function. However, the spatial organization of Sap in its lattice state remains elusive. Here, we employed cryoelectron tomography and subtomogram averaging to obtain a map of the Sap S-layer from tubular polymers that revealed a conformational switch between the postassembly protomers and the previously available X-ray structure of the condensed monomers. To build and validate an atomic model of the lattice within this map, we used a combination of molecular dynamics simulations, X-ray crystallography, cross-linking mass spectrometry, and biophysics in an integrative structural biology approach. The Sap lattice model produced recapitulates a close-to-physiological arrangement, reveals high-resolution details of lattice contacts, and sheds light on the mechanisms underlying the stability of the Sap layer.

A fully human IgG1 antibody targeting connexin 32 extracellular domain blocks CMTX1 hemichannel dysfunction in an in vitro model

Connexins (Cxs) are fundamental in cell–cell communication, functioning as gap junction channels (GJCs) that facilitate solute exchange between adjacent cells and as hemichannels (HCs) that mediate solute exchange between the cytoplasm and the extracellular environment. Mutations in the GJB1 gene, which encodes Cx32, lead to X-linked Charcot-Marie-Tooth type 1 (CMTX1), a rare hereditary demyelinating disorder of the peripheral nervous system (PNS) without an effective cure or treatment. In Schwann cells, Cx32 HCs are thought to play a role in myelination by enhancing intracellular and intercellular Ca2+ signaling, which is crucial for proper PNS myelination. Single-point mutations (p.S85C, p.D178Y, p.F235C) generate pathological Cx32 HCs characterized by increased permeability (“leaky”) or excessive activity (“hyperactive”).We investigated the effects of abEC1.1-hIgG1, a fully human immunoglobulin G1 (hIgG1) monoclonal antibody, on wild-type (WT) and mutant Cx32D178Y HCs. Using HeLa DH cells conditionally co-expressing Cx and a genetically encoded Ca2+ biosensor (GCaMP6s), we demonstrated that mutant HCs facilitated 58% greater Ca2+ uptake in response to elevated extracellular Ca2+ concentrations ([Ca2+]ex) compared to WT HCs. abEC1.1-hIgG1 dose-dependently inhibited Ca2+ uptake, achieving a 50% inhibitory concentration (EC50) of ~ 10 nM for WT HCs and ~ 80 nM for mutant HCs. Additionally, the antibody suppressed DAPI uptake and ATP release. An atomistic computational model revealed that serine 56 (S56) of the antibody interacts with aspartate 178 (D178) of WT Cx32 HCs, contributing to binding affinity. Despite the p.D178Y mutation weakening this interaction, the antibody maintained binding to the mutant HC epitope at sub-micromolar concentrations.In conclusion, our study shows that abEC1.1-hIgG1 effectively inhibits both WT and mutant Cx32 HCs, highlighting its potential as a therapeutic approach for CMTX1. These findings expand the antibody’s applicability for treating diseases associated with Cx HCs and inform the rational design of next-generation antibodies with enhanced affinity and efficacy against mutant HCs.

Mapping the FF domain folding pathway via structures of transiently populated folding intermediates

Despite the tremendous accomplishments of AlpaFold2/3 in predicting biomolecular structure, the protein folding problem remains unsolved in the sense that accurate atomistic models of how protein molecules fold into their native conformations from an unfolded ensemble are still elusive. Here, using chemical exchange saturation transfer (CEST) NMR experiments and a comprehensive four-state kinetic model of the folding trajectory of a 71 residue four-helix bundle FF domain from human HYPA/FBP11 we present an atomic resolution structure of a transiently formed intermediate, I2, that along with the structure of a second intermediate, I1, provides a description of the FF domain folding trajectory. By recording CEST profiles as a function of urea concentration the extent of compaction along the folding pathway is evaluated. Our data establish that unlike the partially disordered I1 state, the I2 intermediate that is also formed before the rate-limiting folding barrier is well ordered and compact like the native conformer, while retaining nonnative interactions similar to those found in I1. The slow-interconversion from I2 to F, involving changes in secondary structure and the breaking of nonnative interactions, proceeds via a compact transition-state. Interestingly, the native state of the FF1 domain from human p190-A Rho GAP resembles the I2 conformation, suggesting that well-ordered folding intermediates can be repurposed by nature in structurally related proteins to assume functional roles. It is anticipated that the strategy for elucidation of sparsely populated and transiently formed structures of intermediates along kinetic pathways described here will be of use in other studies of protein dynamics.

Potential energy landscape formalism for quantum molecular liquids

The potential energy landscape (PEL) formalism is a powerful tool within statistical mechanics to study the thermodynamic properties of classical low-temperature liquids and glasses. Recently, the PEL formalism has been extended to liquids/glasses that obey quantum mechanics, but applications have been limited to atomistic model liquids. In this work, we extend the PEL formalism to liquid/glassy water using path-integral molecular dynamics (PIMD) simulations, where nuclear quantum effects (NQE) are included. Our PIMD simulations, based on the q-TIP4P/F water model, show that the PEL of quantum water is both Gaussian and anharmonic. Importantly, the ring-polymers associated to the O/H atoms in the PIMD simulations, collapse at the local minima of the PEL (inherent structures, IS) for both liquid and glassy states. This allows us to calculate, analytically, the IS vibrational density of states (IS-VDOS) of the ring-polymer system using the IS-VDOS of classical water (obtained from classical MD simulations). The role of NQE on the structural properties of liquid/glassy water at various pressures are discussed in detail. Overall, our results demonstrate that the PEL formalism can effectively describe the behavior of molecular liquids at low temperatures and in the glass states, regardless of whether the liquid/glass obeys classical or quantum mechanics.

Multiscale modeling of short pulse laser induced amorphization of silicon

Silicon surface amorphization by short pulse laser irradiation is a phenomenon of high importance for device manufacturing and surface functionalization. To provide insights into the processes responsible for laser-induced amorphization, a multiscale computational study combining atomistic molecular dynamics simulations of nonequilibrium phase transformations with continuum-level modeling of laser-induced melting and resolidification is performed. Atomistic modeling provides the temperature dependence of the melting/solidification front velocity, predicts the conditions for the transformation of the undercooled liquid to the amorphous state, and enables the parametrization of the continuum model. Continuum modeling, performed for laser pulse durations from 30 ps to 1.5 ns, beam diameters from 5 to 70 μm, and wavelengths of 532, 355, and 1064 nm, reveals the existence of two threshold fluences for the generation and disappearance of an amorphous surface region, with the kinetically stable amorphous phase generated at fluences between the lower and upper thresholds. The existence of the two threshold fluences defines the spatial distribution of the amorphous phase within the laser spot irradiated by a pulse with a Gaussian spatial profile. Depending on the irradiation conditions, the formation of a central amorphous spot, an amorphous ring pattern, and the complete recovery of the crystalline structure are predicted in the simulations. The decrease in the pulse duration or spot diameter leads to an accelerated cooling at the crystal–liquid interface and contributes to the broadening of the range of fluences that produce the amorphous region at the center of the laser spot. The dependence of the amorphization conditions on laser fluence, pulse duration, wavelength, and spot diameter, revealed in the simulations, provides guidance for the development of new applications based on controlled, spatially resolved amorphization of the silicon surface.

The effects of cell displacement on DNA damages in targeted radiation therapy using Geant4-DNA

Charged particle radiation can, directly and indirectly, affect cells by breaking DNA strands. This effect includes DNA single-strand breaks (SSB) and DNA double-strand breaks (DSB), which may cause cell death and mitotic failure. Thus, using short-range charged particles such as Auger electrons (AEs) not only leads to the destruction of the target cell but also prevents the nearby healthy cells from exposing to ionizing radiation. In this study, two spherical cells (C and C2) and their cell nucleus, both made of liquid water, were modeled. An atomic DNA model constructed in the Geant4-DNA Monte Carlo (MC) simulation toolkit was placed inside the nucleus of the C and C2 cells. The number of direct and indirect SSB, DSB, and hybrid DSB (HDSB), caused by some of the most widely-used Auger electron-emitting (AEE) radionuclides, including 99mTc, 111In, 123I, 125I, and 201Tl, distributed within different compartments of the C cell, was calculated in the C and C2 cells, considering the distance between the surface of the two cells ranges from 0 to 5 μm. The present work aimed to investigate the biological effects of AEE radionuclides and their potential for cancer treatment through targeted radiation therapy. The results indicate the impact of 201Tl > 125I > 123I > 111In > 99mTc on DNA damage when the target is C (first spherical cell). On the other hand, for C2 at distances of 0 to 5 μm, the impact of 99mTc > 123I > 111In > 201Tl > 125I on DNA damage is observed.

Skyrmion soliton motion on periodic substrates by atomistic and particle-based simulations

We compare the dynamical behavior of magnetic skyrmions interacting with square and triangular defect arrays just above commensuration using both atomistic and particle-based models. Under applied drives, the initial motion is a kink traveling through the pinned skyrmion lattice. For the square defect array, both models agree well and show a regime in which the soliton motion is locked along 45°. The atomistic model also produces locking of a soliton along 30°, which is absent in the particle-based model. For the triangular defect array, the atomistic model exhibits 30° soliton motion over a wide region of external current values. In contrast, the particle-based model gives 45° soliton motion over a small range of external driving force values. The difference arises because the nondeforming particle model facilitates meandering skyrmion orbits while the deformable atomistic model enables stronger skyrmion-skyrmion interactions that reduce the meandering. Our results indicate that soliton motion through pinned skyrmion lattices on a periodic substrate is a robust effect.

Theoretical study of the temperature dependence of Auger-Meitner recombination in (Al,Ga)N quantum wells.

Non-radiative Auger-Meitner recombination processes in III-nitride based optoelectronic devices operating in the visible spectral range have received significant attention in recent years as they can present a major contribution to the efficiency drop at high temperatures and carrier densities. However, insight into these recombination processes is sparse for III-N devices operating in the ultraviolet wavelength window. In this work we target the temperature dependence of the Auger-Meitner recombination rate in (Al,Ga)N/AlN quantum wells by means of an atomistic electronic structure model that accounts for random alloy fluctuations and connected carrier localisation effects. Our calculations show that in the low temperature regime both the non-radiative Auger-Meitner and radiative recombination rate are strongly impacted by alloy disorder induced carrier localisation effects in these systems. The influence of alloy disorder on the recombination rates is reduced in the high temperature regime, especially for the radiative rate. The Auger-Meitner recombination rate, however, may still be more strongly impacted by alloy disorder when compared to the radiative rate. Our calculations show that while on average radiative recombination slightly increases with increasing temperature, the Auger-Meitner recombination process may, on average, slightly decrease in the temperature range relevant to the thermal efficiency drop (thermal droop). This finding suggests that the considered Auger-Meitner recombination process is unlikely to be directly responsible for the thermal efficiency drop observed experimentally in (Al,Ga)N/AlN quantum well based light emitting devices. Thus, different non-radiative processes, external to the active region, may be the underlying cause of thermal droop in (Al,Ga)N wells.

Съвременен атомистичен модел на изкуството. Част трета

The Contemporary Atomistic Model of Art sought represents an ontogenetic process of creation, communication and perception of the artwork in the environment that surrounds us and that is within us. Instead of immutable wholes (holism), we have infinite sets of processes of connection and disconnection, merging and splitting of “nuclei” (atomism) where interactions are clearly visible. Through art, thought of as the porous structure of society with permeable sites of relation, each image and each material form of an artwork is only a connective element with values and other forms that are transferable in society. This is a principle of dynamic connection in which form is a kind of representation and a potential condition of exchange. The in-between zone has been distinguished, bearing its own traditions and recognizing both the connectedness as well as the separate items that are connected. Fluid culture atomism (fluid atomism) is where we observe the dynamics in interactions in an ever-changing structure that is itself made up of separated atomic units briefly grouped into more complex molecular formations, with all the connections between them being impermanent and temporary. Both the internal structures and the state of the whole change. The interactions of individual units are a key factor in the analysis of processes in art. These processes are embedded in perishable, dynamically transforming networks of ‘private’ art worlds, the sum of which is not the Universal World but a momentary state in an ever-changing system. The relationship between the individual artist and the overall system of organized artistic life passes through interactions of a socialpsychological type in organized temporary groups of artists. This article discusses the possible relations between the field of social psychology and art. Emphasis is placed on the aspects of innovative artistic inquiry, discussed as the singular and the unique in art as opposed to the established order. Innovation in art is juxtaposed with innovation in social bonding as a social psychological problem of creativity. Individual creativity is compared to the creativity of groups and the particularities of the creative processes inherent to individual artists. Such an interpretation develops further the idea of an art world seen as impermanent and dynamically changing networks of ‘private’ art worlds. Among the autonomous zones defined by the individual and the group are found shared zones through which polar differences are harmonized. Individual artistic innovation is juxtaposed with innovative practices that are formed through the action of the groups.

Effect of Hydrogen Content on the Microstructure, Mechanical Properties, and Fracture Mechanism of Low-Carbon Lath Martensite Steel

The effect of hydrogen content on the microstructure, mechanical properties, and fracture mechanisms of low-carbon lath martensitic steel was investigated using both experimental methods and atomistic modeling. Tensile testing revealed a transition in the fracture behavior with increases in hydrogen concentration. Specifically, at a hydrogen content of 0.44 wppm, a shift from transgranular to intergranular fractures was observed. The most probable cause of hydrogen embrittlement was identified to be HELP-mediated HEDE. As the hydrogen concentration increased, the dislocation density in close-packed planes, such as (111) and (100), was found to rise. The key differences between the hydrogen-free and hydrogen-charged specimens were the localization and density of dislocations, as well as the change in the distribution of slip bands. Atomistic modeling supported these experimental findings, showing that “quasi-cleavage” cracks predominantly initiate at block boundaries with higher local hydrogen accumulation. These results underscore the significant role of hydrogen in modifying both the microstructural characteristics and fracture behavior of low-carbon martensitic steel, with important implications for its performance in hydrogen-rich environments.

Redefining the Electron with regard to Augmented Newtonian Dynamics

This paper presents a novel model of the electron according to Augmented Newtonian Dynamics, extending Newtonian dynamics into the sub-atomic level. The paper challenges the conventional understanding of quantum mechanics, particularly the wave-particle duality and the resulting wave-function paradigm. It begins by critiquing the historical adoption of duality to resolve issues like the radiative instability of electrons in atomic orbits, as highlighted by the Larmor formula. The author contends that while duality helped stabilize atomic models, experimental evidence—such as the Lamb shift—indicates that the electron can be more accurately described without invoking wave-particle duality. The proposed model describes the electron as a stable, solid particle that regulates its energy around the nucleus by continually emitting and absorbing virtual photons and in this way self- regulating its energy and preventing it from falling into the nucleus through a dissipation of its energy through radiation. The paper introduces the concept of zero energy in a nuanced and regulated manner showing that it occupies the whole of the Universe. This network, termed the virtual photon field or dark matter (aether), permeates all of space and plays a fundamental role in electromagnetic radiation and gravity.

Neural network potential for dislocation plasticity in ceramics

Dislocations in ceramics are increasingly recognized for their promising potential in applications such as toughening intrinsically brittle ceramics and tailoring functional properties. However, the atomistic simulation of dislocation plasticity in ceramics remains challenging due to the complex interatomic interactions characteristic of ceramics, which include a mix of ionic and covalent bonds, and highly distorted and extensive dislocation core structures within complex crystal structures. These complexities exceed the capabilities of empirical interatomic potentials. Therefore, constructing neural network potentials (NNPs) emerges as the optimal solution. Yet, creating a training dataset that includes dislocation structures proves difficult due to the complexity of their core configurations in ceramics and the computational demands of density functional theory for large atomic models containing dislocation cores. In this work, we propose a training dataset from properties that are easier to compute via high-throughput calculation. Using this dataset, we have successfully developed NNPs for dislocation plasticity in ceramics, specifically for three typical functional ceramics: ZnO, GaN, and SrTiO3. These NNPs effectively capture the nonstoichiometric and charged core structures and slip barriers of dislocations, as well as the long-range electrostatic interactions between charged dislocations. The effectiveness of this dataset was further validated by measuring the similarity and uncertainty across snapshots derived from large-scale simulations, alongside extensive validation across various properties. Utilizing the constructed NNPs, we examined dislocation plasticity in ceramics through nanopillar compression and nanoindentation, which demonstrated excellent agreement with experimental observations. This study provides an effective framework for constructing NNPs that enable the detailed atomistic modeling of dislocation plasticity, opening new avenues for exploring the plastic behavior of ceramics.

Optical constants of magnetron sputtered aluminum in the range 17–1300 eV with improved accuracy and ultrahigh resolution in the L absorption edge region

This work determines a new set of EUV/x-ray optical constants for aluminum (Al), one of the most important materials in science and technology. Absolute photoabsorption (transmittance) measurements in the 17–1300 eV spectral range were performed on freestanding Al films protected by carbon (C) layers, to prevent oxidation. The dispersive portion of the refractive index was obtained via the Kramers–Kronig transformation. Our data provide significant improvements in accuracy compared to previously tabulated values and reveal fine structure in the Al L1 and L2,3 regions, with photon energy step sizes as small as 0.02 eV. The implications of this work in the successful realization of EUV/x-ray instruments and in the validation of atomic and molecular physics models are also discussed.

Unveiling the synergistic deformation mechanism in three-dimensional continuous network graphene-reinforced copper matrix composites

Three-dimensional continuous graphene-reinforced copper matrix composites (3D-Gr/Cu) have excellent mechanical properties due to their special configuration and strengthening mechanisms. To figure out the deformation mechanism of 3D-Gr/Cu, atomic models of 3D-Gr/Cu with different configuration of graphene network (GN) and concentration of defects are constructed and studied by molecular dynamic simulations in this work. Atomic structure evolution during stretching process is investigated, and the mechanical properties of 3D-Gr/Cu, GN and Cu models are studied. Thereby, synergistic deformation between GN and Cu in 3D-Gr/Cu is revealed, and the deformation coordination between GN and Cu is regulated by GN structure and Gr/Cu interface. Furthermore, intrinsic defects in graphene with a suitable concentration help to construct the three-dimensional GN, improve the Gr/Cu interface bonding, and thus enhance the deformation coordination between GN and Cu. These results provide a profound explanation of the deformation mechanism and a new basis for defect engineering in 3D-Gr/Cu.

Evaluating the diffusion of Kr in UO2 and ADOPTTM using time-of-flight elastic recoil detection analysis (ToF-erda)

ABSTRACT A combination of 300 keV 84Kr ion implantation and Time-of-Flight Elastic Recoil Detection Analysis is utilised to investigate the diffusion of Kr in UO2 and ADOPTTM fuels. Composition depth-profiles on the nanometer scale were obtained, both for as-implanted samples and after annealing at 800°C for 1 h. Observed drifts in the 84Kr profiles could be associated with short-range diffusion mechanisms. The approach employed here provides the possibility to make direct comparisons with atomistic scale modelling data, and can be of service as a separate effect test in line with the Accelerated Fuel Qualification initiative.