First Principles Calculations for Corrosion in Mg-Li-Al Alloys with Focus on Corrosion Resistance: A Comprehensive Review

This comprehensive review examines the structural,mechanical,electronic,and thermodynamic properties of Mg-Li-Al alloys,focusing on their corrosion resistance and mechanical performance enhancement.Utilizing first-principles calculations based on Density Functional Theory(DFT)and the quasi-harmonic approximation(QHA),the combined properties of the Mg-Li-Al phase are explored,revealing superior incompressibility,shear resistance,and stiffness compared to individual elements.The review highlights the brittleness of the alloy,supported by B/G ratios,Cauchy pressures,and Poisson’s ratios.Electronic structure analysis shows metallic behavior with varied covalent bonding characteristics,while Mulliken population analysis emphasizes significant electron transfer within the alloy.This paper also studied thermodynamic properties,including Debye temperature,heat capacity,enthalpy,free energy,and entropy,which are precisely examined,highlighting the Mg-Li-Al phase sensitive to thermal conductivity and thermal performance potential.Phonon density of states(PHDOS)confirms dynamic stability,while anisotropic sound velocities reveal elastic anisotropies.This comprehensive review not only consolidates the current understanding of the Mg-Li-Al alloy’s properties but also proposes innovative strategies for enhancing corrosion resistance.Among these strategies is the introduction of a corrosion barrier akin to the Mg-Li-Al network,which holds promise for advancing both the applications and performance of these alloys.This review serves as a crucial foundation for future research aimed at optimizing alloy design and processing methods.

First-principles calculations of Ni–(Co)–Mn–Cu–Ti all-d-metal Heusler alloy on martensitic transformation,mechanical and magnetic properties

The martensitic transformation,mechanical,and magnetic properties of the Ni_(2)Mn_(1.5-x)Cu_(x)Ti_(0.5) (x=0.125,0.25,0.375,0.5) and Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5)[(x=0.125,y=0.125,0.25,0.375,0.5) and (x=0.125,0.25,0.375,y=0.625)]alloys were systematically studied by the first-principles calculations.For the formation energy,the martensite is smaller than the austenite,the Ni–(Co)–Mn–Cu–Ti alloys studied in this work can undergo martensitic transformation.The austenite and non-modulated (NM) martensite always present antiferromagnetic state in the Ni_(2)Mn_(1.5-x)Cu_(x)Ti_(0.5) and Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5) (y<0.625) alloys.When y=0.625 in the Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5) series,the austenite presents ferromagnetic state while the NM martensite shows antiferromagnetic state.Cu doping can decrease the thermal hysteresis and anisotropy of the Ni–(Co)–Mn–Ti alloy.Increasing Mn and decreasing Ti content can improve the shear resistance and normal stress resistance,but reduce the toughness in the Ni–Mn–Cu–Ti alloy.And the ductility of the Co–Cu co-doping alloy is inferior to that of the Ni–Mn–Cu–Ti and Ni–Co–Mn–Ti alloys.The electronic density of states was studied to reveal the essence of the mechanical and magnetic properties.

Rational design of Fe/Co-based diatomic catalysts for Li–S batteries by first-principles calculations

Fe/Co-based diatomic catalysts decorated on an N-doped graphene substrate are investigated by first-principles calculations to improve the electrochemical properties of Li–S batteries.Our results demonstrate that Fe CoN8@Gra not only possesses moderate adsorption energies towards Li2Snspecies,but also exhibits superior catalytic activity for both reduction and oxidation reactions of the sulfur cathode.Moreover,the metallic property of the diatomic catalysts can be well maintained after Li2Snadsorption,which could help the sulfur cathode to maintain high conductivity during the whole charge–discharge process.Given these exceptional properties,it is expected that Fe CoN8@Gra could be a promising diatomic catalyst for Li–S batteries and afford insights for further development of advanced Li–S batteries.

Direct atomic-level insight into oxygen reduction reaction on size-dependent Pt-based electrocatalysts from density functional theory calculations

Developing novel oxygen reduction reaction(ORR)catalysts with high activity is urgent for proton exchange membrane fuel cells.Herein,we investigated a group of size-dependent Pt-based catalysts as promising ORR catalysts by density functional theory calculations,ranging from single-atom,nanocluster to bulk Pt catalysts.The results showed that the ORR overpotential of these Pt-based catalysts increased when its size enlarged to the nanoparticle scale or reduced to the single-atom scale,and the Pt_(38)cluster had the lowest ORR overpotential(0.46 V)compared with that of Pt_(111)(0.57 V)and single atom Pt(0.7 V).Moreover,we established a volcano curve relationship between the ORR overpotential and binding energy of O*(ΔE_(O*),confirming the intermediate species anchored on Pt38cluster with suitable binding energy located at top of volcano curve.The interaction between intermediate species and Pt-based catalysts were also investigated by the charge distribution and projected density of state and which further confirmed the results of volcano curve.

Benchmarking calculations of excitation energies and transition properties with spectroscopic accuracy of highly charged ions used for the fusion plasma and astrophysical plasma

Atomic radiative data such as excitation energies, transition wavelengths, radiative rates, and level lifetimes with high precision are the essential parameters for the abundance analysis, simulation, and diagnostics in fusion and astrophysical plasmas. In this work, we mainly focus on reviewing our two projects performed in the past decade. One is about the ions with Z■30 that are generally of astrophysical interest, and the other one is about the highly charged krypton(Z = 36)and tungsten(Z = 74) ions that are relevant in research of magnetic confinement fusion. Two different and independent methods, namely, multiconfiguration Dirac–Hartree–Fock(MCDHF) and the relativistic many-body perturbation theory(RMBPT) are usually used in our studies. As a complement/extension to our previous works for highly charged tungsten ions with open M-shell and open N-shell, we also mainly focus on presenting and discussing our complete RMBPT and MCDHF calculations for the excitation energies, wavelengths, electric dipole(E1), magnetic dipole(M1), electric quadrupole(E2), and magnetic quadrupole(M2) transition properties, and level lifetimes for the lowest 148 levels belonging to the 3l3configurations in Al-like W61+. We also summarize the uncertainties of our systematical theoretical calculations, by cross-checking/validating our datasets from our RMBPT and MCDHF calculations, and by detailed comparisons with available accurate observations and other theoretical calculations. The data are openly available in Science Data Bank at https://doi.org/10.57760/sciencedb.10569.

Passivation of PEA^(+)to CsPbI_(3)(110)Surface States:From the First Principles Calculations

This work investigates the effect of passivation on the electronic properties of inorganic perovskite CsPbI_(3)materials by using first-principles calculations with density functional theory(DFT).The passivation effect after the addition of Phenylethylamine(PEA+)molecule to CsPbI_(3)(110)surface is studied.The results of density of states(DOS)calculations show that the CsPbI_(3)(110)surface model with I atom terminated reveals new electronic DOS peaks(surface states)near the Fermi level.These surface states are mainly due to the contribution of I-5p orbital and are harmful to the CsPbI_(3)-based solar cells because they reduce the photoelectric conversion efficiency.The surface states near the Fermi level are significantly reduced,and the decline rate reaches 38.8%with the addition with PEA+molecule to the CsPbI3(110)surface.

Structural,electronic,and Li-ion mobility properties of garnet-type Li_(7)La_(3)Zr_(2)O_(12) surface:An insight from first-principles calculations

Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) is a promising solid-state electrolyte for Li-ion batteries,but Li-dendrite's formation greatly limits the applications.In this paper,we systematically investigate the stability,electronic properties,and Li-ion mobility of the LLZO surface by the ifrst-principles calculations.We consider the(110) and(001) slab structures with different terminations in the t-and c-LLZO.Our results indicate that both(110) and(001) surfaces prefer to form Li-rich termination due to their low surface energies for either t-or c-LLZO.Moreover,with the decrease of Li contents the stability of Li-rich surfaces is improved initially and degrades later.Unfortunately,the localized surface states at the Fermi level can induce the formation of metallic Li on the Li-rich surfaces.In comparison,Li/La-termination has a relatively low metallic Li formation tendency due to its rather low diffusion barrier.In fact,Li-ion can spontaneously migrate along path II(Li3→Li2) on the Li/La-T(001) surface.In contrast,it is more difficult for Li-ion diffusion on the Li-T(001) surface,which has a minimum diffusion barrier of 0.50 eV.Interestingly,the minimum diffusion barrier decreases to 0.34 eV when removing four Li-ions from the Li-T(001) surface.Thus,our study suggests that by varying Li contents,the stability and Li-ion diffusion barrier of LLZO surfaces can be altered favorably.These advantages can inhibit the formation of metallic Li on the LLZO surfaces.

Design of high-performance ion-doped CoP systems for hydrogen evolution:From multi-level screening calculations to experiment

Rational design of high-performance electrocatalysts for hydrogen evolution reaction(HER)is vital for future renewable energy systems.The incorporation of foreign metal ions into catalysts can be an effective approach to optimize its performance.However,there is a lack of systematic theoretical studies to reveal the quantitative relationships at the electronic level.Here,we develop a multi-level screening methodology to search for highly stable and active dopants for CoP catalysts.The density functional theory(DFT)calculations and symbolic regression(SR)were performed to investigate the relationship between the adsorption free energy(ΔG_(H^(*)))and 10 electronic parameters.The mathematic formulas derived from SR indicate that the difference of work function(ΔΦ)between doped metal and the acceptor plays the most important role in regulatingΔG_(H^(*)),followed by the d-band center(d-BC)of doped system.The descriptor of HER can be expressed asΔG_(H^(*))=1.59×√|0.188ΔΦ+d BC+0.120|1/2-0.166 with a high determination coefficient(R^(2)=0.807).Consistent with the theoretical prediction,experimental results show that the Al-CoP delivers superior electrocatalytic HER activity with a low overpotential of75 m V to drive a current density of 10 mA cm^(-2),while the overpotentials for undoped CoP,Mo-CoP,and V-CoP are 206,134,and 83 m V,respectively.The current work proves that theΔΦis the most significant regulatory parameter ofΔG_(H^(*))for ion-doped electrocatalysts.This finding can drive the discovery of high-performance ion-doped electrocatalysts,which is crucial for electrocatalytic water splitting.

The effects of combining alloying elements on the elastic properties of γ-Ni in Ni-based superalloy:High-throughput first-principles calculations

Using high-throughput first-principles calculations, we systematically studied the synergistic effect of alloying two elements （AI and 28 kinds of 3d, 4d, and 5d transition metals） on the elastic constants and elastic moduli of γ-Ni. We used machine learning to theoretically predict the relationship between alloying concentration and mechanical properties, giving the binding energy between the two elements. We found that the ternary alloying elements strengthened the 7 phase in the order of Re 〉 Ir 〉 W 〉 Ru 〉 Cr 〉 Mo 〉 Pt 〉 Ta 〉 Co. There is a quadratic parabolic relationship between the number of d shell electrons in the alloying element and the bulk modulus, and the maximum bulk modulus appears when the d shell is half full. We found a linear relationship between bulk modulus and alloying concentration over a certain alloying range. Using linear regression, we found the linear fit concentration coefficient of 29 elements. Using machine learning to theoretically predict the bulk modulus and lattice constants of Ni32XY, we predicted values close to the calculated results, with a regression parameter of R2 = 0.99626. Compared with pure Ni, the alloyed Ni has higher bulk modulus B, G, E, Cll, and C44, but equal Cl2. The alloying strengthening in some of these systems is closely tied to the binding of elements, indicating that the binding energy of the alloy is a way to assess its elastic properties.

Structural and Electronic Properties of ConC3-/0 and ConC4-/0 （n=1-4） Clusters： Mass-Selected Anion Photoelectron Spectroscopy and Density Functional Theory Calculations

We investigated the structural evolution and elecfronic properties of ConC3-/0 and ConC4-/0 （n=1-4） clusters by using mass-selected photoelectron spectroscopy and density functional theory calculations. The adiabatic and vertical detachment energies of CO1-4C3- and COl-4C4- were obtained from their photoelectron spectra. By comparing the theoretical results with the experimental data, the global minimum structures were determined. The results indicate that the carbon atoms of ConC3-/0 and ConC4-/0 （n=1-4） are separated from each other gradually with increasing number of cobalt atoms but a C2 unit still remains at n=4. It is interesting that the Co2C3- and Co2C4- anions have planar structures whereas the neutral Co2C3 and Co2C4 have linear structures with the Co atoms at two ends. The Co3C3- anion has a planar structure with a Co2C2 four-membered ring and a Co3C four-membered ring sharing a Co-Co bond, while the neutral Co3C3 is a three-dimensional structure with a C2 unit and a C atom connecting to two faces of the Co3 triangle.

Dipole Moments of the Bioactive Constituents Present in Flutab Drug by Ab-Initio Calculations

Many of the technology and computational chemistry applications are used to study drugs and their biological effects. Flutab&reg;drug contains Paracetamol, Diphenhydramine and Pseudoephedrine. Ab-initio calculations were performed at DFT/B3LYP and HF methods with three basis sets, namely, STO-3G, 3-21G, and 6-31G(d) in order to calculate the dipole moments of the three constituents of Flutab&reg;drug. The Diphenhydramine compound was found to be the most stable constituent, with the lowest value of dipole moment.

Comparisons between numerical calculations and measurements in vaned diffuser of SHF impeller

The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have already been performed at middle height inside one diffuser channel passage for a given speed of rotation and various mass flow rates.These results have been already presented in several previous communications.New experiments have been performed using a three-hole pressure probe traverses from hub to shroud diffuser width at different radial locations between the two diffuser geometrical throats.Numerical simulations are also realized with the commercial codes Star CCM+7.02.011 and CFX.Frozen rotor and fully unsteady calculations of the whole pump have been performed.Comparisons between numerical results,previous experimental PIV results and new probe traverses one's are presented and discussed for one mass flow rate.In this respect,a first attempt to take into account fluid leakages between the rotating and fixed part of the pump has been checked since it may affects the real flow structure inside the diffuser.

First-principles calculations of structural,elastic and electronic properties of(TaNb)0.67(HfZrTi)0.33 high-entropy alloy under high pressure

To clarify the effect of pressure on a(TaNb)0.67(HfZrTi)0.33 alloy composed of a solid solution with a single body-centered-cubic crystal structure,we used first-principles calculations to theoretically investigate the structural,elastic,and electronic properties of this alloy at different pressures.The results show that the calculated equilibrium lattice parameters are consistent with the experimental results,and that the normalized structural parameters of lattice constants and volume decrease whereas the total enthalpy differenceΔE and elastic constants increase with increasing pressure.The(TaNb)0.67(HfZrTi)0.33 alloy exhibits mechanical stability at high pressures lower than 400 GPa.At high pressure,the bulk modulus B shows larger values than the shear modulus G,and the alloy exhibits an obvious anisotropic feature at pressures ranging from 30 to 70 GPa.Our analysis of the electronic structures reveals that the atomic orbitals are occupied by the electrons change due to the compression of the crystal lattices under the effect of high pressure,which results in a decrease in the total density of states and a wider electron energy level.This factor is favorable for zero resistance.

Comparative study of Mo2Ga2C with superconducting MAX phase Mo2GaC： First-principles calculations

The structural, electronic, optical and thermodynamic properties of Mo2Ga2C are investigated using density func- tional theory （DFT） within the generalized gradient approximation （GGA）. The optimized crystal structure is obtained and the lattice parameters are compared with available experimental data. The electronic density of states （DOS） is calculated and analyzed. The metallic behavior for the compound is confirmed and the value of DOS at Fermi level is 4.2 states per unit cell per eV. Technologically important optical parameters （e.g., dielectric function, refractive index, absorption coefficient, photo conductivity, reflectivity, and loss function） are calculated for the first time. The study of dielectric constant （ε1） indicates the Drude-like behavior. The absorption and conductivity spectra suggest that the compound is metallic. The reflectance spectrum shows that this compound has the potential to be used as a solar reflector. The thermodynamic properties such as the temperature and pressure dependent bulk modulus, Debye temperature, specific heats, and thermal expansion coefficient of Mo2Ga2C MAX phase are derived from the quasi-harmonic Debye model with phononic effect also for the first time. Analysis of Tc expression using available parameter values （DOS, Debye temperature, atomic mass, etc.） suggests that the compound is less likely to be superconductor.

Ab Initio Calculations of the Electronic Structures of Copper Pyrites CuS2, CuSe2 and CuTe2

The electronic structures of CuS2, CuSe2 and CuTe2 with pyrite structures, within the framework the density-functional theory have been investigated. The calculated results explained the recent experimental results which show that there is no clear indication of strong electron correlations in the electronic properties of Cu pyrites, due to the dominant chalcogen p character rather than d characteristic of Cu at the Fermi level.

First-principles calculations and experimental studies of Sn-Zn alloys as negative electrode materials for lithium-ion batteries

The physical characters and electrochemical properties of various phases in a Sn-Zn electrode, such as formation energy, plateau potential, specific capacity, as well as volume expansion, were calculated by the first-principles plane-wave pseudo-potential method based on the den- sity functional theory. Sn-Zn films were also deposited on copper foils by an electroless plating technique. The actual composition and chemical characters were explored by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, plasma atomic emission spectrometry （ICP）, and constant current charge/discharge measurements （CC）. The results show that separation phases with tin and zinc including a small quantity of Cu6Sn5 phase were obtained, the initial lithium insertion capacity of the Sn-Zn film was 661 mAh/g, and obvious potential pla- teaus of about 0.4 V and 0.7 V were displayed, which is in accordance with the results of theoretical calculations. The capacity of the Sn-Zn film decreased seriously with the increase of cycle number.

Electronic and optical properties of anion-doped c-ZrO_2 from first-principles calculations

Using the first-principles calculations based on density functional theory(DFT),the structure stability,electronic and some optical properties of C and N doped cubic ZrO2(c-ZrO2) in 24-atom systems were investigated.It is found from the formation energies calculations that N ions are easier to be doped into c-ZrO2 than C ions.The electronic structure results show that Zr8O15C and Zr8O15N systems are semiconductors with the band gap of 2.3 eV and 2.8 eV,respectively,which are lower than that of the pure ZrO2(3.349 eV).And optical properties results depict that anion doping,especially C adding,can enhance the static dielectric function,visible and ultraviolet light absorption and reflecting ability of c-ZrO2 crystal.

Performance of the CENDL-3.2 and other major neutron data libraries for criticality calculations

Nuclear data are the cornerstones of reactor physics and shielding calculations.Recently,China released CENDL-3.2 in 2020,and the US released ENDF/B-VIII.0 in 2018.Therefore,it is necessary to comprehensively evaluate the criticality computing performance of these newly released evaluated nuclear libraries.In this study,we used the NJOY2016 code to generate ACE format libraries based on the latest neutron data libraries(including CENDL-3.2,JEFF3.3,ENDF/B-VIII.0,and JENDL4.0).The MCNP code was used to conduct a detailed analysis of fission nuclides,including^(235)U,^(233)U,and^(239)Pu,in different evaluated nuclear data libraries based on 100 benchmarks.The criticality calculation performance of each library was evaluated using three statistical parameters:δk/σ,χ^(2),and<|Δ|>.Analysis of theδk/σparameter showed that CENDL-3.1 and JENDL-4.0 both had>10 benchmarks that exceeded 3r,whereas CENDL3.2,ENDFB-VIII.0,and JEFF-3.3 had,7,5,and 4 benchmarks,respectively,exceeding 3r.The ENDF/B-VII.1 library performed best,with only two benchmarks exceeding 3r.Compared to CENDL-3.1,CENDL-3.2 offers an improvement in criticality calculations.Compared to the JEFF-3.3 and ENDF/B-VIII.0 libraries,CENDL3.2 performs better in the calculation of the^(233)U assemblies,but it performs poorly in the pusl11 series case calculation of the^(239)Pu assemblies,and thus further improvement is needed.

Transition‐metal‐atom‐pairs deposited on g‐CN monolayer for nitrogen reduction reaction:Density functional theory calculations

The development of highly active DFT catalysts for an electrocatalytic N_(2)reduction reaction(NRR)under mild conditions is a difficult challenge.In this study,a series of atom‐pair catalysts(APCs)for an NRR were fabricated using transition‐metal(TM)atoms(TM=Sc−Zn)doped into g‐CN monolayers.The electrochemical mechanism of APCs for an NRR has been reported by well‐defined density functional theory calculations.The calculated limiting potentials were−0.47 and−0.78 V for the Fe_(2)@CN and Co_(2)@CN catalysts,respectively.Owing to its high suppression of hydrogen evolution reactions,Co_(2)@CN is a superior electrocatalytic material for a N_(2)fixation.Stable Fe_(2)@CN may be a strongly attractive material for an NRR with a relatively low overpotential after an improvement in the selectivity.The two‐way charge transfer affirmed the donation‐acceptance procedure between N_(2)and Fe_(2)@CN or Co_(2)@CN,which play a crucial role in the activation of inert N≡N bonds.This study provides an in‐depth investigation into atom‐pair catalysts and will open up new avenues for highly efficient g‐CN‐based nanostructures for an NRR.

Mechanical properties of Mn-doped ZnO nanowires studied by first-principles calculations

First-principles calculations were performed to investigate the mechanical properties of ZnO nanowires and to study the doping and size effects. A series of strains were applied to ZnO nanowires in the axial direction and the elastic moduli of ZnO nanowires were obtained from the energy versus strain curves. Pure and Mn-doped ZnO nanowires with three different diameters （1.14, 1.43, and 1.74 nm） were studied. It is found that the elastic moduli of the ZnO nanowires are 146.5, 146.6, and 143.9 GPa, respectively, which are slightly larger than that of the bulk （140.1 GPa）, and they increase as the diameter decreases. The elastic moduli of the Mn-doped ZnO nanowires are 137.6, 141.8, and 141.0 GPa, which are slightly lower than those of the undoped ones by 6.1%, 3.3%, and 2.0%, respectively. The mechanisms of doping and size effect were discussed in terms of chemical bonding and geometry considerations.