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PolyMLP_Seko_2022p1_LiTi__MO_671224571016_000

Interatomic potential for Lithium (Li), Titanium (Ti).
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Title
A single sentence description.
Polynomial machine learning potential for Li-Ti developed by Seko (2022) v000
Description
A short description of the Model describing its key features including for example: type of model (pair potential, 3-body potential, EAM, etc.), modeled species (Ac, Ag, ..., Zr), intended purpose, origin, and so on.
Polynomial machine learning potential (MLP) for Li-Ti system. This potential is gtinv-257 potential in Li-Ti-2022-06-12 taken from Polynomial MLP Repository. The RMS errors for energy and forces are 6.562 meV/atom and 0.1004 eV/angstrom, respectively. The estimated computational cost required for a single core calculation is 0.79 ms/atom/step.
Species
The supported atomic species.
Li, Ti
Disclaimer
A statement of applicability provided by the contributor, informing users of the intended use of this KIM Item.
Several models from the PolyMLP repository are available for LiTi, all laying on a pareto front of computational speed vs. RMS accuracy. They are labeled p1, p2, p3, p4, p5 in their KIM IDs. Higher numbers mean slower models. The author-recommended model for this system is p1 (this model).
Content Origin PolyMLP Repository (Kyoto University) https://cms.mtl.kyoto-u.ac.jp/seko/mlp-repository/index.html
Contributor Atsuto Seko
Maintainer Atsuto Seko
Developer Atsuto Seko
Published on KIM 2026
How to Cite

This Model originally published in [1] is archived in OpenKIM [2-5].

[1] Seko A. Tutorial: Systematic development of polynomial machine learning potentials for elemental and alloy systems. J Appl Phys. 2023Jan;133(1). doi:10.1063/5.0129045 — (Primary Source) A primary source is a reference directly related to the item documenting its development, as opposed to other sources that are provided as background information.

[2] Seko A. Polynomial machine learning potential for Li-Ti developed by Seko (2022) v000. OpenKIM; 2026. doi:10.25950/29b9876a

[3] Seko A. Model driver for polynomial machine learning potentials (PolyMLP) ported from pypolymlp v000. OpenKIM; 2026. doi:10.25950/948ad72c

[4] Tadmor EB, Elliott RS, Sethna JP, Miller RE, Becker CA. The potential of atomistic simulations and the Knowledgebase of Interatomic Models. JOM. 2011;63(7):17. doi:10.1007/s11837-011-0102-6

[5] Elliott RS, Tadmor EB. Knowledgebase of Interatomic Models (KIM) Application Programming Interface (API). OpenKIM; 2011. doi:10.25950/ff8f563a

Funding Not available
Short KIM ID
The unique KIM identifier code.
MO_671224571016_000
Extended KIM ID
The long form of the KIM ID including a human readable prefix (100 characters max), two underscores, and the Short KIM ID. Extended KIM IDs can only contain alpha-numeric characters (letters and digits) and underscores and must begin with a letter.
PolyMLP_Seko_2022p1_LiTi__MO_671224571016_000
DOI 10.25950/29b9876a
https://doi.org/10.25950/29b9876a
https://commons.datacite.org/doi.org/10.25950/29b9876a
KIM Item Type
Specifies whether this is a Portable Model (software implementation of an interatomic model); Portable Model with parameter file (parameter file to be read in by a Model Driver); Model Driver (software implementation of an interatomic model that reads in parameters).
Portable Model using Model Driver PolyMLP__MD_367995833009_000
DriverPolyMLP__MD_367995833009_000
KIM API Version2.3
Potential Type polymlp

(Click here to learn more about Verification Checks)

Grade Name Category Brief Description Full Results Aux File(s)
P vc-periodicity-support mandatory
Periodic boundary conditions are handled correctly; see full description.
Results Files
P vc-permutation-symmetry mandatory
Total energy and forces are unchanged when swapping atoms of the same species; see full description.
Results Files
P vc-objectivity informational
Total energy is unchanged and forces transform correctly under rigid-body translation and rotation; see full description.
Results Files
P vc-inversion-symmetry informational
Total energy is unchanged and forces change sign when inverting a configuration through the origin; see full description.
Results Files
P vc-memory-leak informational
The model code does not have memory leaks (i.e. it releases all allocated memory at the end); see full description.
Results Files
P vc-unit-conversion mandatory
The model is able to correctly convert its energy and/or forces to different unit sets; see full description.
Results Files
P vc-contributing-atom-energy informational
other
Results Files


BCC Lattice Constant

This bar chart plot shows the mono-atomic body-centered cubic (bcc) lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Li


Cohesive Energy Graph

This graph shows the cohesive energy versus volume-per-atom for the current mode for four mono-atomic cubic phases (body-centered cubic (bcc), face-centered cubic (fcc), simple cubic (sc), and diamond). The curve with the lowest minimum is the ground state of the crystal if stable. (The crystal structure is enforced in these calculations, so the phase may not be stable.) Graphs are generated for each species supported by the model.

Species: Ti
Species: Li


Diamond Lattice Constant

This bar chart plot shows the mono-atomic face-centered diamond lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Ti
Species: Li


Dislocation Core Energies

This graph shows the dislocation core energy of a cubic crystal at zero temperature and pressure for a specific set of dislocation core cutoff radii. After obtaining the total energy of the system from conjugate gradient minimizations, non-singular, isotropic and anisotropic elasticity are applied to obtain the dislocation core energy for each of these supercells with different dipole distances. Graphs are generated for each species supported by the model.

(No matching species)

FCC Elastic Constants

This bar chart plot shows the mono-atomic face-centered cubic (fcc) elastic constants predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Li
Species: Ti


FCC Lattice Constant

This bar chart plot shows the mono-atomic face-centered cubic (fcc) lattice constant predicted by the current model (shown in red) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Ti
Species: Li


FCC Stacking Fault Energies

This bar chart plot shows the intrinsic and extrinsic stacking fault energies as well as the unstable stacking and unstable twinning energies for face-centered cubic (fcc) predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

(No matching species)

FCC Surface Energies

This bar chart plot shows the mono-atomic face-centered cubic (fcc) relaxed surface energies predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

(No matching species)

SC Lattice Constant

This bar chart plot shows the mono-atomic simple cubic (sc) lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Ti
Species: Li


Cubic Crystal Basic Properties Table

Species: Li

Species: Ti



Disclaimer From Model Developer

Several models from the PolyMLP repository are available for LiTi, all laying on a pareto front of computational speed vs. RMS accuracy. They are labeled p1, p2, p3, p4, p5 in their KIM IDs. Higher numbers mean slower models. The author-recommended model for this system is p1 (this model).



Cohesive energy versus lattice constant curve for monoatomic cubic lattices v003

Creators:
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/64cb38c5

This Test Driver uses LAMMPS to compute the cohesive energy of a given monoatomic cubic lattice (fcc, bcc, sc, or diamond) at a variety of lattice spacings. The lattice spacings range from a_min (=a_min_frac*a_0) to a_max (=a_max_frac*a_0) where a_0, a_min_frac, and a_max_frac are read from stdin (a_0 is typically approximately equal to the equilibrium lattice constant). The precise scaling and number of lattice spacings sampled between a_min and a_0 (a_0 and a_max) is specified by two additional parameters passed from stdin: N_lower and samplespacing_lower (N_upper and samplespacing_upper). Please see README.txt for further details.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Cohesive energy versus lattice constant curve for bcc Li v004 view 151414
Cohesive energy versus lattice constant curve for diamond Li v004 view 154270
Cohesive energy versus lattice constant curve for diamond Ti v004 view 152386
Cohesive energy versus lattice constant curve for fcc Li v004 view 244680
Cohesive energy versus lattice constant curve for fcc Ti v004 view 151110
Cohesive energy versus lattice constant curve for sc Ti v004 view 164660


Elastic constants for arbitrary crystals at zero temperature and pressure v001

Creators:
Contributor: ilia
Publication Year: 2025
DOI: https://doi.org/10.25950/922d328f

Computes the elastic constants for an arbitrary crystal. A robust computational protocol is used, attempting multiple methods and step sizes to achieve an acceptably low error in numerical differentiation and deviation from material symmetry. The crystal structure is specified using the AFLOW prototype designation as part of the Crystal Genome testing framework. In addition, the distance from the obtained elasticity tensor to the nearest isotropic tensor is computed.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Elastic constants for Ti in AFLOW crystal prototype A_cF4_225_a at zero temperature and pressure v001 view 528060
Elastic constants for Li in AFLOW crystal prototype A_cI2_229_a at zero temperature and pressure v001 view 634560
Elastic constants for Ti in AFLOW crystal prototype A_cI2_229_a at zero temperature and pressure v001 view 472287
Elastic constants for Li in AFLOW crystal prototype A_hR3_166_ac at zero temperature and pressure v001 view 828566
Elastic constants for Li in AFLOW crystal prototype A_oP6_51_ak at zero temperature and pressure v001 view 2321700


Elastic constants for cubic crystals at zero temperature and pressure v006

Creators: Junhao Li and Ellad Tadmor
Contributor: tadmor
Publication Year: 2019
DOI: https://doi.org/10.25950/5853fb8f

Computes the cubic elastic constants for some common crystal types (fcc, bcc, sc, diamond) by calculating the hessian of the energy density with respect to strain. An estimate of the error associated with the numerical differentiation performed is reported.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Elastic constants for bcc Li at zero temperature v006 view 29306
Elastic constants for diamond Li at zero temperature v001 view 72790
Elastic constants for diamond Ti at zero temperature v001 view 49440
Elastic constants for fcc Li at zero temperature v006 view 54684
Elastic constants for fcc Ti at zero temperature v006 view 21752
Elastic constants for sc Li at zero temperature v006 view 14704
Elastic constants for sc Ti at zero temperature v006 view 32628


Equilibrium structure and energy for a crystal structure at zero temperature and pressure v003

Creators:
Contributor: ilia
Publication Year: 2025
DOI: https://doi.org/10.25950/866c7cfa

Computes the equilibrium crystal structure and energy for an arbitrary crystal at zero temperature and applied stress by performing symmetry-constrained relaxation. The crystal structure is specified using the AFLOW prototype designation. Multiple sets of free parameters corresponding to the crystal prototype may be specified as initial guesses for structure optimization. No guarantee is made regarding the stability of computed equilibria, nor that any are the ground state.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Equilibrium crystal structure and energy for Li in AFLOW crystal prototype A_cF4_225_a v003 view 175914
Equilibrium crystal structure and energy for Ti in AFLOW crystal prototype A_cF4_225_a v003 view 190847
Equilibrium crystal structure and energy for Li in AFLOW crystal prototype A_cI2_229_a v003 view 122674
Equilibrium crystal structure and energy for Ti in AFLOW crystal prototype A_cI2_229_a v003 view 187870
Equilibrium crystal structure and energy for Li in AFLOW crystal prototype A_cP4_213_a v003 view 171751
Equilibrium crystal structure and energy for Li in AFLOW crystal prototype A_hP1_191_a v003 view 144540
Equilibrium crystal structure and energy for Li in AFLOW crystal prototype A_hP2_194_c v003 view 135677
Equilibrium crystal structure and energy for Ti in AFLOW crystal prototype A_hP2_194_c v003 view 149160
Equilibrium crystal structure and energy for Ti in AFLOW crystal prototype A_hP3_191_ad v003 view 150960
Equilibrium crystal structure and energy for Li in AFLOW crystal prototype A_hR3_166_ac v003 view 191848
Equilibrium crystal structure and energy for Li in AFLOW crystal prototype A_oP6_51_ak v003 view 202878


Test driver for computing reference ground state structures and energies for each element at zero temperature and applied stress v000

Creators:
Contributor: efuem
Publication Year: 2025
DOI: https://doi.org/10.25950/fa5ed729

This test returns reference ground state structures and energies for each element at zero temperature and applied stress. The results from this test are useful when a reference structure is required in some downstream test, such as vacancy tests (used as a reservoir). This test driver works by querying results from the EquilibriumCrystalStructure test driver using element specific reference structures following CHIPS-FF. Although the reference prototypes are independent of model, the resulting structure and energy of the prototypes are model-dependent.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Reference elemental energy for Li v000 view 36752


Equilibrium lattice constant and cohesive energy of a cubic lattice at zero temperature and pressure v007

Creators: Daniel S. Karls and Junhao Li
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/2765e3bf

Equilibrium lattice constant and cohesive energy of a cubic lattice at zero temperature and pressure.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Equilibrium zero-temperature lattice constant for bcc Li v007 view 36120
Equilibrium zero-temperature lattice constant for diamond Li v007 view 39955
Equilibrium zero-temperature lattice constant for diamond Ti v007 view 40284
Equilibrium zero-temperature lattice constant for fcc Li v007 view 19869
Equilibrium zero-temperature lattice constant for fcc Ti v007 view 45400
Equilibrium zero-temperature lattice constant for sc Li v007 view 35231
Equilibrium zero-temperature lattice constant for sc Ti v007 view 32160


Equilibrium lattice constants for hexagonal bulk structures at zero temperature and pressure v005

Creators: Daniel S. Karls and Junhao Li
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/c339ca32

Calculates lattice constant of hexagonal bulk structures at zero temperature and pressure by using simplex minimization to minimize the potential energy.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Equilibrium lattice constants for hcp Li v005 view 242068


Linear thermal expansion coefficient of cubic crystal structures v002

Creators:
Contributor: mjwen
Publication Year: 2024
DOI: https://doi.org/10.25950/9d9822ec

This Test Driver uses LAMMPS to compute the linear thermal expansion coefficient at a finite temperature under a given pressure for a cubic lattice (fcc, bcc, sc, diamond) of a single given species.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Linear thermal expansion coefficient of bcc Li at 293.15 K under a pressure of 0 MPa v002 view 105643101


High-symmetry surface energies in cubic lattices and broken bond model v004

Creators: Matt Bierbaum
Contributor: mattbierbaum
Publication Year: 2019
DOI: https://doi.org/10.25950/6c43a4e6

Calculates the surface energy of several high symmetry surfaces and produces a broken-bond model fit. In latex form, the fit equations are given by:

E_{FCC} (\vec{n}) = p_1 (4 \left( |x+y| + |x-y| + |x+z| + |x-z| + |z+y| +|z-y|\right)) + p_2 (8 \left( |x| + |y| + |z|\right)) + p_3 (2 ( |x+ 2y + z| + |x+2y-z| + |x-2y + z| + |x-2y-z| + |2x+y+z| + |2x+y-z| +|2x-y+z| +|2x-y-z| +|x+y+2z| +|x+y-2z| +|x-y+2z| +|x-y-2z| ) + c

E_{BCC} (\vec{n}) = p_1 (6 \left( | x+y+z| + |x+y-z| + |-x+y-z| + |x-y+z| \right)) + p_2 (8 \left( |x| + |y| + |z|\right)) + p_3 (4 \left( |x+y| + |x-y| + |x+z| + |x-z| + |z+y| +|z-y|\right)) +c.

In Python, these two fits take the following form:

def BrokenBondFCC(params, index):

import numpy
x, y, z = index
x = x / numpy.sqrt(x**2.+y**2.+z**2.)
y = y / numpy.sqrt(x**2.+y**2.+z**2.)
z = z / numpy.sqrt(x**2.+y**2.+z**2.)

return params[0]*4* (abs(x+y) + abs(x-y) + abs(x+z) + abs(x-z) + abs(z+y) + abs(z-y)) + params[1]*8*(abs(x) + abs(y) + abs(z)) + params[2]*(abs(x+2*y+z) + abs(x+2*y-z) +abs(x-2*y+z) +abs(x-2*y-z) + abs(2*x+y+z) +abs(2*x+y-z) +abs(2*x-y+z) +abs(2*x-y-z) + abs(x+y+2*z) +abs(x+y-2*z) +abs(x-y+2*z) +abs(x-y-2*z))+params[3]

def BrokenBondBCC(params, x, y, z):


import numpy
x, y, z = index
x = x / numpy.sqrt(x**2.+y**2.+z**2.)
y = y / numpy.sqrt(x**2.+y**2.+z**2.)
z = z / numpy.sqrt(x**2.+y**2.+z**2.)

return params[0]*6*(abs(x+y+z) + abs(x-y-z) + abs(x-y+z) + abs(x+y-z)) + params[1]*8*(abs(x) + abs(y) + abs(z)) + params[2]*4* (abs(x+y) + abs(x-y) + abs(x+z) + abs(x-z) + abs(z+y) + abs(z-y)) + params[3]
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Broken-bond fit of high-symmetry surface energies in bcc Li v004 view 6155413


Vacancy formation and migration energies for cubic and hcp monoatomic crystals v001

Creators:
Contributor: efuem
Publication Year: 2023
DOI: https://doi.org/10.25950/c27ba3cd

Computes the monovacancy formation and migration energies for cubic and hcp monoatomic crystals.
Test Test Results Link to Test Results page Benchmark time
Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run.

Measured in Millions of Whetstone Instructions (MWI)
Vacancy formation and migration energy for bcc Li view 25502552




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