× Updated! Potentials that share interactions are now listed as related models.
 
Citation: Y. Zuo, C. Chen, X. Li, Z. Deng, Y. Chen, J. Behler, G. Csányi, A.V. Shapeev, A.P. Thompson, M.A. Wood, and S.P. Ong (2020), "Performance and Cost Assessment of Machine Learning Interatomic Potentials", The Journal of Physical Chemistry A, 124(4), 731-745. DOI: 10.1021/acs.jpca.9b08723.
Abstract: Machine learning of the quantitative relationship between local environment descriptors and the potential energy surface of a system of atoms has emerged as a new frontier in the development of interatomic potentials (IAPs). Here, we present a comprehensive evaluation of machine learning IAPs (ML-IAPs) based on four local environment descriptors—atom-centered symmetry functions (ACSF), smooth overlap of atomic positions (SOAP), the spectral neighbor analysis potential (SNAP) bispectrum components, and moment tensors—using a diverse data set generated using high-throughput density functional theory (DFT) calculations. The data set comprising bcc (Li, Mo) and fcc (Cu, Ni) metals and diamond group IV semiconductors (Si, Ge) is chosen to span a range of crystal structures and bonding. All descriptors studied show excellent performance in predicting energies and forces far surpassing that of classical IAPs, as well as predicting properties such as elastic constants and phonon dispersion curves. We observe a general trade-off between accuracy and the degrees of freedom of each model and, consequently, computational cost. We will discuss these trade-offs in the context of model selection for molecular dynamics and other applications.

Notes: This is the SNAP Mo potential from the reference.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
Citation: Y. Zuo, C. Chen, X. Li, Z. Deng, Y. Chen, J. Behler, G. Csányi, A.V. Shapeev, A.P. Thompson, M.A. Wood, and S.P. Ong (2020), "Performance and Cost Assessment of Machine Learning Interatomic Potentials", The Journal of Physical Chemistry A, 124(4), 731-745. DOI: 10.1021/acs.jpca.9b08723.
Abstract: Machine learning of the quantitative relationship between local environment descriptors and the potential energy surface of a system of atoms has emerged as a new frontier in the development of interatomic potentials (IAPs). Here, we present a comprehensive evaluation of machine learning IAPs (ML-IAPs) based on four local environment descriptors—atom-centered symmetry functions (ACSF), smooth overlap of atomic positions (SOAP), the spectral neighbor analysis potential (SNAP) bispectrum components, and moment tensors—using a diverse data set generated using high-throughput density functional theory (DFT) calculations. The data set comprising bcc (Li, Mo) and fcc (Cu, Ni) metals and diamond group IV semiconductors (Si, Ge) is chosen to span a range of crystal structures and bonding. All descriptors studied show excellent performance in predicting energies and forces far surpassing that of classical IAPs, as well as predicting properties such as elastic constants and phonon dispersion curves. We observe a general trade-off between accuracy and the degrees of freedom of each model and, consequently, computational cost. We will discuss these trade-offs in the context of model selection for molecular dynamics and other applications.

Notes: This is the qSNAP Mo potential from the reference.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
Citation: C. Chen, Z. Deng, R. Tran, H. Tang, I.-H. Chu, and S.P. Ong (2017), "Accurate force field for molybdenum by machine learning large materials data", Physical Review Materials, 1(4), 043603. DOI: 10.1103/physrevmaterials.1.043603.
Abstract: In this work, we present a highly accurate spectral neighbor analysis potential (SNAP) model for molybdenum (Mo) developed through the rigorous application of machine learning techniques on large materials data sets. Despite Mo's importance as a structural metal, existing force fields for Mo based on the embedded atom and modified embedded atom methods do not provide satisfactory accuracy on many properties. We will show that by fitting to the energies, forces, and stress tensors of a large density functional theory (DFT)-computed dataset on a diverse set of Mo structures, a Mo SNAP model can be developed that achieves close to DFT accuracy in the prediction of a broad range of properties, including elastic constants, melting point, phonon spectra, surface energies, grain boundary energies, etc. We will outline a systematic model development process, which includes a rigorous approach to structural selection based on principal component analysis, as well as a differential evolution algorithm for optimizing the hyperparameters in the model fitting so that both the model error and the property prediction error can be simultaneously lowered. We expect that this newly developed Mo SNAP model will find broad applications in large and long-time scale simulations.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
Citation: J.-S. Kim, D. Seol, J. Ji, H.-S. Jang, Y. Kim, and B.-J. Lee (2017), "Second nearest-neighbor modified embedded-atom method interatomic potentials for the Pt-M (M = Al, Co, Cu, Mo, Ni, Ti, V) binary systems", Calphad, 59, 131-141. DOI: 10.1016/j.calphad.2017.09.005.
Abstract: Interatomic potentials for Pt-M (M = Al, Co, Cu, Mo, Ni, Ti, V) binary systems have been developed on the basis of the second nearest-neighbor modified embedded-atom method (2NN MEAM) formalism. The parameters of pure Mo have also been newly developed to solve a problem in the previous 2NN MEAM potential in which the sigma and α-Mn structures become more stable than the bcc structure. The potentials reproduce various materials properties of alloys (structural, thermodynamic and order-disorder transition temperature) in reasonable agreements with relevant experimental data and other calculations. The applicability of the developed potentials to atomistic investigations for the shape and atomic configuration of Pt bimetallic nanoparticles is demonstrated.

LAMMPS pair_style meam (2017--Kim-J-S--Mo--LAMMPS--ipr1)
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Notes: These potential files were obtained from http://cmse.postech.ac.kr/home_2nnmeam, accessed Nov 9, 2020. For consistency, the "library.meam_alloy" file for the interaction was renamed here to "Mo.meam".
File(s):
Citation: R.S. Elliott, and A. Akerson (2015), "Efficient "universal" shifted Lennard-Jones model for all KIM API supported species".

Notes: This is the Mo interaction from the "Universal" parameterization for the openKIM LennardJones612 model driver.The parameterization uses a shifted cutoff so that all interactions have a continuous energy function at the cutoff radius. This model was automatically fit using Lorentz-Berthelotmixing rules. It reproduces the dimer equilibrium separation (covalent radii) and the bond dissociation energies. It has not been fitted to other physical properties and its ability to model structures other than dimers is unknown. See the README and params files on the KIM model page for more details.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
Citation: H. Park, M.R. Fellinger, T.J. Lenosky, W.W. Tipton, D.R. Trinkle, S.P. Rudin, C. Woodward, J.W. Wilkins, and R.G. Hennig (2012), "Ab initio based empirical potential used to study the mechanical properties of molybdenum", Physical Review B, 85(21), 214121. DOI: 10.1103/physrevb.85.214121.
Abstract: Density-functional theory energies, forces, and elastic constants determine the parametrization of an empirical, modified embedded-atom method potential for molybdenum. The accuracy and transferability of the potential are verified by comparison to experimental and density-functional data for point defects, phonons, thermal expansion, surface and stacking fault energies, and ideal shear strength. Searching the energy landscape predicted by the potential using a genetic algorithm verifies that it reproduces not only the correct bcc ground state of molybdenum but also all low-energy metastable phases. The potential is also applicable to the study of plastic deformation and used to compute energies, core structures, and Peierls stresses of screw and edge dislocations.

LAMMPS pair_style meam/spline (2012--Park-H--Mo--LAMMPS--ipr1)
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Notes: These files were contributed by Dr. Michael Fellinger (The Ohio State Univ.) and posted with his permission. The file Park_Mo_2012_bcc.in contains a simple script to demonstrate the use of this interatomic potential with LAMMPS. It was tested on the 1Feb2014 version of LAMMPS with USER-MISC enabled.
File(s):
Citation: P.M. Derlet, D. Nguyen-Manh, and S.L. Dudarev (2007), "Multiscale modeling of crowdion and vacancy defects in body-centered-cubic transition metals", Physical Review B, 76(5), 054107. DOI: 10.1103/physrevb.76.054107.
Abstract: We investigate the structure and mobility of single self-interstitial atom and vacancy defects in body-centered-cubic transition metals forming groups 5B (vanadium, niobium, and tantalum) and 6B (chromium, molybdenum, and tungsten) of the Periodic Table. Density-functional calculations show that in all these metals the axially symmetric ⟨111⟩ self-interstitial atom configuration has the lowest formation energy. In chromium, the difference between the energies of the ⟨111⟩ and the ⟨110⟩ self-interstitial configurations is very small, making the two structures almost degenerate. Local densities of states for the atoms forming the core of crowdion configurations exhibit systematic widening of the “local” d band and an upward shift of the antibonding peak. Using the information provided by electronic structure calculations, we derive a family of Finnis-Sinclair-type interatomic potentials for vanadium, niobium, tantalum, molybdenum, and tungsten. Using these potentials, we investigate the thermally activated migration of self-interstitial atom defects in tungsten. We rationalize the results of simulations using analytical solutions of the multistring Frenkel-Kontorova model describing nonlinear elastic interactions between a defect and phonon excitations. We find that the discreteness of the crystal lattice plays a dominant part in the picture of mobility of defects. We are also able to explain the origin of the non-Arrhenius diffusion of crowdions and to show that at elevated temperatures the diffusion coefficient varies linearly as a function of absolute temperature.

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Notes: Listing found at https://openkim.org.
Link(s):
Citation: X.W. Zhou, R.A. Johnson, and H.N.G. Wadley (2004), "Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers", Physical Review B, 69(14), 144113. DOI: 10.1103/physrevb.69.144113.
Abstract: Recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multilayers have revealed the formation of misfit-strain-reducing dislocation structures very similar to those observed experimentally. Here we report similar simulations showing the formation of edge dislocations near the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multilayers. Unlike misfit dislocations that accommodate lattice mismatch, the dislocation structures observed here increase the mismatch strain energy. Stop-action observations of the dynamically evolving atomic structures indicate that during deposition on the (111) surface of a fcc lattice, adatoms may occupy either fcc sites or hcp sites. This results in the random formation of fcc and hcp domains, with dislocations at the domain boundaries. These dislocations enable atoms to undergo a shift from fcc to hcp sites, or vice versa. These shifts lead to missing atoms, and therefore a later deposited layer can have missing planes compared to a previously deposited layer. This dislocation formation mechanism can create tensile stress in fcc films. The probability that such dislocations are formed was found to quickly diminish under energetic deposition conditions.

FORTRAN (2004--Zhou-X-W--Mo--FORTRAN--ipr1)
Notes: These are the original files sent by X.W. Zhou (Sandia National Laboratory) and posted with his permission. C.A. Becker (NIST) modified create.f to include the reference in the generated potential files and the EAM.input file for this composition. These files can be used to generate alloy potentials for Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Fe, Mo, Ta, W, Mg, Co, Ti, and Zr by editing EAM.input. However, as addressed in the reference, these potentials were not designed for use with metal compounds.
File(s): superseded


LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Mo--LAMMPS--ipr1)
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Notes: This file was generated by C.A. Becker (NIST) from create.f and posted with X.W. Zhou's (Sandia National Laboratory) permission.
File(s): superseded


FORTRAN (2004--Zhou-X-W--Mo--FORTRAN--ipr2)
Notes: The file Zhou04_create_v2.f is an updated version of create.f modified by L.M. Hale (NIST) following advice from X.W. Zhou (Sandia National Laboratory). This version removes spurious fluctuations in the tabulated functions of the original potential files caused by single/double precision floating point number conflicts.
File(s):
LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Mo--LAMMPS--ipr2)
See Computed Properties
Notes: This file was generated by L.M. Hale from Zhou04_create_v2.f on 13 April 2018 and posted with X.W. Zhou's (Sandia National Laboratory) permission. This version corrects an issue with spurious fluctuations in the tabulated functions.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Mo--LAMMPS--ipr1.
Link(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Mo--LAMMPS--ipr2.
Link(s):
Citation: S. Han, L.A. Zepeda-Ruiz, G.J. Ackland, R. Car, and D.J. Srolovitz (2003), "Interatomic potential for vanadium suitable for radiation damage simulations", Journal of Applied Physics, 93(6), 3328-3335. DOI: 10.1063/1.1555275.
Abstract: The ability to predict the behavior of point defects in metals, particularly interstitial defects, is central to accurate modeling of the microstructural evolution in environments with high radiation fluxes. Existing interatomic potentials of embedded atom method type predict disparate stable interstitial defect configurations in vanadium. This is not surprising since accurate first-principles interstitial data were not available when these potentials were fitted. In order to provide the input information required to fit a vanadium potential appropriate for radiation damage studies, we perform a series of first-principles calculations on six different interstitial geometries and vacancies. These calculations identify the 〈111〉 dumbbell as the most stable interstitial with a formation energy of approximately 3.1 eV, at variance with predictions based upon existing potentials. Our potential is of Finnis–Sinclair type and is fitted exactly to the experimental equilibrium lattice parameter, cohesive energy, elastic constants and a calculated unrelaxed vacancy formation energy. Two additional potential parameters were used to obtain the best fit to the set of interstitial formation energies determined from the first-principles calculations. The resulting potential was found to accurately predict both the magnitude and ordering of the formation energies of six interstitial configurations and the unrelaxed vacancy ground state, in addition to accurately describing the migration characteristics of the stable interstitial and vacancy. This vanadium potential is capable of describing the point defect properties appropriate for radiation damage simulations as well as for simulations of more common crystal and simple defect properties.

Moldy FS (2003--Han-S--Mo--MOLDY--ipr1)
Notes: The parameters in Mo.moldy were obtained from http://homepages.ed.ac.uk/graeme/moldy/moldy.html and posted with the permission of G.J. Ackland.
File(s):
Citation: B.-J. Lee, M.I. Baskes, H. Kim, and Y.K. Cho (2001), "Second nearest-neighbor modified embedded atom method potentials for bcc transition metals", Physical Review B, 64(18), 184102. DOI: 10.1103/physrevb.64.184102.
Abstract: The second nearest-neighbor modified embedded atom method (MEAM) [Phys. Rev. B 62, 8564 (2000)], developed in order to solve problems of the original first nearest-neighbor MEAM on bcc metals, has now been applied to all bcc transition metals, Fe, Cr, Mo, W, V, Nb, and Ta. The potential parameters could be determined empirically by fitting to (∂B/∂P), elastic constants, structural energy differences among bcc, fcc and hcp structures, vacancy-formation energy, and surface energy. Various physical properties of individual elements, including elastic constants, structural properties, point-defect properties, surface properties, and thermal properties were calculated and compared with experiments or high level calculations so that the reliability of the present empirical atomic-potential formalism can be evaluated. It is shown that the present potentials reasonably reproduce nonfitted properties of the bcc transition metals, as well as the fitted properties. The effect of the size of radial cutoff distance on the calculation and the compatibility with the original first nearest-neighbor MEAM that has been successful for fcc, hcp, and other structures are also discussed.

LAMMPS pair_style meam (2001--Lee-B-J--Mo--LAMMPS--ipr1)
See Computed Properties
Notes: These potential files were obtained from http://cmse.postech.ac.kr/home_2nnmeam, accessed Nov 9, 2020.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
Citation: G.J. Ackland, and R. Thetford (1987), "An improved N-body semi-empirical model for body-centred cubic transition metals", Philosophical Magazine A, 56(1), 15-30. DOI: 10.1080/01418618708204464.
Abstract: The recently published semi-empirical potentials of Finnis and Sinclair for the metals V, Nb, Ta, Mo and W appear to give unphysical results for properties involving small interatomic separation. This is remedied by adding to the potentials cores fitted to electron gas calculations on dimers. The adjusted potentials are shown to predict a more realistic pressure-volume relationship. Interstitial formation energies are calculated for various configurations, using quenched molecular dynamics and static relaxation. Some preliminary results on interstitial migration are presented.

Equations (1987--Ackland-G-J--Mo--parameters--ipr1)
Notes: The file AckThet.pdf was obtained from http://homepages.ed.ac.uk/graeme/moldy/moldy.html and posted with the permission of G.J. Ackland.
File(s):
LAMMPS pair_style eam/fs (1987--Ackland-G-J--Mo--LAMMPS--ipr1)
See Computed Properties
Notes: This implementation has been retracted as it was identified as having an incorrect functional form. It is made available solely for archival purposes.
File(s): retracted


LAMMPS pair_style eam/alloy (1987--Ackland-G-J--Mo--LAMMPS--ipr2)
See Computed Properties
Notes: This file was provided by Sergei Starikov (Ruhr-Universität Bochum, Germany) on 5 May 2019. It has been carefully tested and gives the expected property predictions. Update March 15, 2020: This version was identified to not be compatible with LAMMPS versions after 7 Aug 2019 due to more rigorous format checks.
File(s): superseded


LAMMPS pair_style eam/alloy (1987--Ackland-G-J--Mo--LAMMPS--ipr3)
See Computed Properties
Notes: This file was created by Lucas Hale and posted on 15 March 2020. It is a modification of the parameter file in the above version to be compatible with LAMMPS versions after 7 Aug 2019. It contains the same parameter tables and should behave identically to the last version, and work with any version of LAMMPS.
File(s):
Citation: L.A. Girifalco, and V.G. Weizer (1959), "Application of the Morse Potential Function to Cubic Metals", Physical Review, 114(3), 687-690. DOI: 10.1103/physrev.114.687.
Abstract: The Morse parameters were calculated using experimental values for the energy of vaporization, the lattice constant, and the compressibility. The equation of state and the elastic constants which were computed using the Morse parameters, agreed with experiment for both face-centered and body-centered cubic metals. All stability conditions were also satisfied for both the face-centered and the body-centered metals. This shows that the Morse function can be applied validly to problems involving any type of deformation of the cubic metals.

See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is the "low cutoff" variation.
Link(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is the "medium cutoff" variation.
Link(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is the "high cutoff" variation.
Link(s):
 
Citation: J. Wang, S.-H. Oh, and B.-J. Lee (2020), "Second-nearest-neighbor modified embedded-atom method interatomic potential for Cu-M (M = Co, Mo) binary systems", Computational Materials Science, 178, 109627. DOI: 10.1016/j.commatsci.2020.109627.
Abstract: Second-nearest-neighbor modified embedded-atom method (2NN MEAM) interatomic potentials for Cu-M (M = Co, Mo) binary systems have been developed. The Cu-M potentials can be extended to Pt-Cu-M ternary 2NN MEAM potentials being combined with already existing Pt-M potentials and can be utilized for atomistic simulations to design inexpensive and efficient platinum alloy catalysts. The potentials reproduce fundamental material properties such as structural and thermodynamic properties of compound and solution phases in reasonable agreement with experimental data. Herein, the validity of the developed potentials for atomistic simulation is ascertained.

LAMMPS pair_style meam (2020--Wang-J--Cu-Mo--LAMMPS--ipr1)
See Computed Properties
Notes: These potential files were obtained from http://cmse.postech.ac.kr/home_2nnmeam, accessed Nov 9, 2020.
File(s):
 
Citation: X.-G. Li, C. Chen, H. Zheng, Y. Zuo, and S.P. Ong (2020), "Complex strengthening mechanisms in the NbMoTaW multi-principal element alloy", npj Computational Materials, 6(1), 70. DOI: 10.1038/s41524-020-0339-0.
Abstract: Refractory multi-principal element alloys (MPEAs) have exceptional mechanical properties, including high strength-to-weight ratio and fracture toughness, at high temperatures. Here we elucidate the complex interplay between segregation, short-range order, and strengthening in the NbMoTaW MPEA through atomistic simulations with a highly accurate machine learning interatomic potential. In the single crystal MPEA, we find greatly reduced anisotropy in the critically resolved shear stress between screw and edge dislocations compared to the elemental metals. In the polycrystalline MPEA, we demonstrate that thermodynamically driven Nb segregation to the grain boundaries (GBs) and W enrichment within the grains intensifies the observed short-range order (SRO). The increased GB stability due to Nb enrichment reduces the von Mises strain, resulting in higher strength than a random solid solution MPEA. These results highlight the need to simultaneously tune GB composition and bulk SRO to tailor the mechanical properties of MPEAs.

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Notes: Listing found at https://openkim.org.
Link(s):
 
Citation: X.-G. Li, C. Hu, C. Chen, Z. Deng, J. Luo, and S.P. Ong (2018), "Quantum-accurate spectral neighbor analysis potential models for Ni-Mo binary alloys and fcc metals", Physical Review B, 98(9), 094104. DOI: 10.1103/physrevb.98.094104.
Abstract: In recent years, efficient interatomic potentials approaching the accuracy of density functional theory (DFT) calculations have been developed using rigorous atomic descriptors satisfying strict invariances, for example, for translation, rotation, permutation of homonuclear atoms, among others. In this paper, we generalize the spectral neighbor analysis potential (SNAP) model to bcc-fcc binary alloy systems. We demonstrate that machine-learned SNAP models can yield significant improvements even over the well-established high-performing embedded atom method (EAM) and modified EAM potentials for fcc Cu and Ni. We also report on the development of a SNAP model for the fcc Ni-bcc Mo binary system by machine learning a carefully constructed large computed data set of elemental and intermetallic compounds. We demonstrate that this binary Ni-Mo SNAP model can achieve excellent agreement with experiments in the prediction of a Ni-Mo phase diagram as well as near-DFT accuracy in the prediction of many key properties, such as elastic constants, formation energies, melting points, etc., across the entire binary composition range. In contrast, the existing Ni-Mo EAM has significant errors in the prediction of the phase diagram and completely fails in binary compounds. This paper provides a systematic model development process for multicomponent alloy systems, including an efficient procedure to optimize the hyperparameters in the model fitting, and paves the way for long-time large-scale simulations of such systems.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
 
Citation: G.-U. Jeong, C.S. Park, H.-S. Do, S.-M. Park, and B.-J. Lee (2018), "Second nearest-neighbor modified embedded-atom method interatomic potentials for the Pd-M (M = Al, Co, Cu, Fe, Mo, Ni, Ti) binary systems", Calphad, 62, 172-186. DOI: 10.1016/j.calphad.2018.06.006.
Abstract: Palladium (Pd) has attracted attention as one of the major components of noble metal catalysts due to its excellent reactivity to a wide range of catalytic reactions. It is important to predict and control the atomic arrangement in catalysts because their properties are known to be affected by it. Therefore, to enable atomistic simulations for investigating the atomic scale structural evolution, we have developed interatomic potentials for Pd-M (M = Al, Co, Cu, Fe, Mo, Ni, Ti) binary systems based on the second nearest-neighbor modified embedded-atom method formalism. These potentials reproduce various fundamental properties of the alloys (the structural, elastic and thermodynamic properties of compound and solution phases, and order-disorder transition temperature) in reasonable agreements with experimental data, first-principles calculations and CALPHAD assessments. Herein, we propose that these potentials can be applied to the design of robust bimetallic catalysts by predicting the shape and atomic arrangement of Pd bimetallic nanoparticles.

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Notes: The meam files were generated from the word file which was obtained from http://cmse.postech.ac.kr/home_2nnmeam.
File(s):
 
Citation: J.-S. Kim, D. Seol, J. Ji, H.-S. Jang, Y. Kim, and B.-J. Lee (2017), "Second nearest-neighbor modified embedded-atom method interatomic potentials for the Pt-M (M = Al, Co, Cu, Mo, Ni, Ti, V) binary systems", Calphad, 59, 131-141. DOI: 10.1016/j.calphad.2017.09.005.
Abstract: Interatomic potentials for Pt-M (M = Al, Co, Cu, Mo, Ni, Ti, V) binary systems have been developed on the basis of the second nearest-neighbor modified embedded-atom method (2NN MEAM) formalism. The parameters of pure Mo have also been newly developed to solve a problem in the previous 2NN MEAM potential in which the sigma and α-Mn structures become more stable than the bcc structure. The potentials reproduce various materials properties of alloys (structural, thermodynamic and order-disorder transition temperature) in reasonable agreements with relevant experimental data and other calculations. The applicability of the developed potentials to atomistic investigations for the shape and atomic configuration of Pt bimetallic nanoparticles is demonstrated.

See Computed Properties
Notes: These potential files were obtained from http://cmse.postech.ac.kr/home_2nnmeam, accessed Nov 9, 2020.
File(s):
 
Citation: M. Wen, S.N. Shirodkar, P. Plecháč, E. Kaxiras, R.S. Elliott, and E.B. Tadmor (2017), "A force-matching Stillinger-Weber potential for MoS2: Parameterization and Fisher information theory based sensitivity analysis", Journal of Applied Physics, 122(24), 244301. DOI: 10.1063/1.5007842.
Abstract: Two-dimensional molybdenum disulfide (MoS2) is a promising material for the next generation of switchable transistors and photodetectors. In order to perform large-scale molecular simulations of the mechanical and thermal behavior of MoS2-based devices, an accurate interatomic potential is required. To this end, we have developed a Stillinger-Weber potential for monolayer MoS2. The potential parameters are optimized to reproduce the geometry (bond lengths and bond angles) of MoS2 in its equilibrium state and to match as closely as possible the forces acting on the atoms along a dynamical trajectory obtained from ab initio molecular dynamics. Verification calculations indicate that the new potential accurately predicts important material properties including the strain dependence of the cohesive energy, the elastic constants, and the linear thermal expansion coefficient. The uncertainty in the potential parameters is determined using a Fisher information theory analysis. It is found that the parameters are fully identified, and none are redundant. In addition, the Fisher information matrix provides uncertainty bounds for predictions of the potential for new properties. As an example, bounds on the average vibrational thickness of a MoS2 monolayer at finite temperature are computed and found to be consistent with the results from a molecular dynamics simulation. The new potential is available through the OpenKIM interatomic potential repository at https://openkim.org/cite/MO_201919462778_000.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
 
Citation: S.V. Starikov, L.N. Kolotova, A.Y. Kuksin, D.E. Smirnova, and V.I. Tseplyaev (2018), "Atomistic simulation of cubic and tetragonal phases of U-Mo alloy: Structure and thermodynamic properties", Journal of Nuclear Materials, 499, 451-463. DOI: 10.1016/j.jnucmat.2017.11.047.
Abstract: We studied structure and thermodynamic properties of cubic and tetragonal phases of pure uranium and U-Mo alloys using atomistic simulations: molecular dynamics and density functional theory. The main attention was paid to the metastable γ0-phase that is formed in U-Mo alloys at low temperature. Structure of γ0-phase is similar to body-centered tetragonal (bct) lattice with displacement of a central atom in the basic cell along [001] direction. Such displacements have opposite orientations for part of the neighbouring basic cells. In this case, such ordering of the displacements can be designated as antiferro-displacement. Formation of such complex structure may be interpreted through forming of short U-U bonds. At heating, the tetragonal structure transforms into cubic γs-phase, still showing ordering of central atom displacements. With rise in temperature, γs-phase transforms to γ-phase with a quasi body-centered cubic (q-bcc) lattice. The local positions of uranium atoms in γ-phase correspond to γs-phase, however, orientations of the central atom displacements become disordered. Transition from γ0 to γ can be considered as antiferro-to paraelastic transition of order-disorder type. \n\nThis approach to the structure description of uranium alloy allows to explain a number of unusual features found in the experiments: anisotropy of lattice at low temperature; remarkably high self-diffusion mobility in γ-phase; decreasing of electrical resistivity at heating for some alloys. In addition, important part of this work is the development of new interatomic potential for U-Mo system made with taking into account details of studied structures.

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Notes: These files were sent by S.V. Starikov (Joint Institute for High Temperatures, Russian Academy of Sciences) on 3 Dec. 2017 and posted with his permission.
File(s): superseded


See Computed Properties
Notes: This file was recieved by Sergei Starikov on August 2, 2018. He noted: "In the previous version, one function for Mo-Mo interaction had poor smoothing with r=r_cut. This "bug" led to the sake of the energy conservation during high-temperature (or long) calculations for pure Mo or U-Mo alloy. I made an additional check and found a small potential compilation issue leading to this energy drift. I fixed the file, so now it can be safely used with the time-step = 0.5 fs, even for long runs at high temperatures (the test was made for 1500K)."
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Citation: D.E. Smirnova, A.Y. Kuksin, S.V. Starikov, V.V. Stegailov, Z. Insepov, J. Rest, and A.M. Yacout (2013), "A ternary EAM interatomic potential for U-Mo alloys with xenon", Modelling and Simulation in Materials Science and Engineering, 21(3), 035011. DOI: 10.1088/0965-0393/21/3/035011.
Abstract: A new interatomic potential for a uranium–molybdenum system with xenon is developed in the framework of an embedded atom model using a force-matching technique and a dataset of ab initio atomic forces. The verification of the potential proves that it is suitable for the investigation of various compounds existing in the system as well as for simulation of pure elements: U, Mo and Xe. Computed lattice constants, thermal expansion coefficients, elastic properties and melting temperatures of U, Mo and Xe are consistent with the experimentally measured values. The energies of the point defect formation in pure U and Mo are proved to be comparable to the density-functional theory calculations. We compare this new U–Mo–Xe potential with the previously developed U and Mo–Xe potentials. A comparative study between the different potential functions is provided. The key purpose of the new model is to study the atomistic processes of defect evolution taking place in the U–Mo nuclear fuel. Here we use the potential to simulate bcc alloys containing 10 wt% of intermetallic Mo and U2Mo.

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Notes: This file was sent by Daria Smirnova (Joint Institute for High Temperatures, Russian Academy of Sciences) and posted on 14 March 2013 with her permission. Update March 15, 2020: This version was identified to not be compatible with LAMMPS versions after 7 Aug 2019 due to more rigorous format checks.
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LAMMPS pair_style hybrid/overlay eam/alloy eam/fs (2013--Smirnova-D-E--U-Mo-Xe--LAMMPS--ipr2)
See Computed Properties
Notes: This corrected file was posted on March 15, 2020. In particular, a single 0.0 value was added to the end to make it compatible with versions of LAMMPS after 7 Aug 2019.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2013--Smirnova-D-E--U-Mo-Xe--LAMMPS--ipr1.
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Citation: Y. Chen, X. Liao, N. Gao, W. Hu, F. Gao, and H. Deng (2020), "Interatomic potentials of W-V and W-Mo binary systems for point defects studies", Journal of Nuclear Materials, 531, 152020. DOI: 10.1016/j.jnucmat.2020.152020.
Abstract: Interatomic potentials for tungsten-vanadium (W-V) and tungsten-molybdenum (W-Mo) binary systems have been developed based on Finnis-Sinclair formalism. The potentials are based on an accurate previously developed potential of pure W. Potential parameters of V-V, Mo-Mo, W-V and W-Mo were determined by fitting to a large database of experimental data as well as first principle calculations. These potentials were able to describe various fundamental physical properties of pure V and Mo, such as a lattice constant, cohesive energy, elastic constants, bulk modulus, vacancy and self-interstitial atom formation energies, stacking fault energies and a relative stability of <100> and ½<111> interstitial dislocation loops. Other fundamental properties of the potentials described included alloy behaviours, such as the formation energies of substitutional solute atoms, binding energies between solute atoms and point defects, formation energies and lattice constants of artificial ordered alloys. These results are in reasonable agreement with experimental or first principle results. Based on these results, the developed potentials are suitable for studying point defect properties and can be further used to explore displacement cascade simulations.

LAMMPS pair_style eam/fs (2020--Chen-Y--W-Mo--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Huiqiu Deng (Hunan University, Changsha, China) on 6 Dec 2022 and posted with his permission.
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Date Created: October 5, 2010 | Last updated: December 14, 2022