Schema Documentation¶

This section contains auto-generated documentation for the NOMAD simulations schema.

The schema is organized into vertical domains, each covering a specific aspect of simulation metadata:

Simulation Entry ¶

Root entry point for simulations: Simulation, BaseSimulation, and Program

In scope: Root Simulation section that contains all simulation metadata, Timing information (cpu1_start, cpu1_end, wall_start, wall_end), Program details (name, version, link), Entry point that references the four main subsections

Key sections: Simulation, BaseSimulation, Program

Model System ¶

Root ModelSystem section with direct representation relationships and complete system tree

In scope: ModelSystem as the root of the system tree, Recursive sub_systems containment (ModelSystem contains ModelSystem), System type and dimensionality, Direct relationships to Representation and AlternativeRepresentation, References to ParticleState, Local/Global symmetry, and ChemicalFormula subsections

Key sections: ModelSystem, Representation, AlternativeRepresentation

Alternative Representations ¶

AlternativeRepresentation subsection details: transforms and mapping to a reference representation

In scope: AlternativeRepresentation subsection of ModelSystem, Reference representation linkage, Transformation matrix and origin shift between representations, How alternative cells are mapped from the original representation

Key sections: AlternativeRepresentation

Particle States ¶

Complete particle state hierarchy: ParticleState base class, AtomsState with detailed atomic properties, and CGBeadState

In scope: ParticleState: base class for all particle information, AtomsState: atomic particle states with chemical symbols, CGBeadState: coarse-grained bead states, AtomicOrbitals: quantum numbers (n, l, ml, j, mj, ms) within AtomsState, Orbital degeneracy and occupation, CoreHole: excited electron states for spectroscopy, HubbardInteractions: U matrix, U_effective, J_Hunds for correlated systems, Slater integrals for many-body interactions, Particle indices, velocities, forces, Chemical symbols and particle organization

Key sections: ParticleState, AtomsState, CGBeadState, AtomicOrbitals, CoreHole, HubbardInteractions

Symmetry ¶

Crystallographic symmetry: local/global symmetry, space groups, point groups, Bravais lattices

In scope: Local and global symmetry section hierarchy, Space group symbols and numbers, Point group symbols, Bravais lattice classifications, Symmetry operations

Key sections: LocalSymmetry, LocalCrystalSymmetry, GlobalSymmetry, GlobalCrystalSymmetry

Chemical Formula ¶

Chemical formulas in different formats: descriptive, reduced, IUPAC, Hill, anonymous

In scope: Descriptive formula, Reduced formula, IUPAC formula, Hill formula, Anonymous formula, Automatic formula generation

Key sections: ChemicalFormula

Model Method ¶

Base method hierarchy up to ModelMethodElectronic

In scope: Top-level inheritance chain: BaseModelMethod → ModelMethod → ModelMethodElectronic, Entry point for all electronic-method subclasses

Key sections: BaseModelMethod, ModelMethod, ModelMethodElectronic

Model Method Electronic ¶

Electronic method subclasses branching from ModelMethodElectronic

In scope: Electronic-method inheritance rooted at ModelMethodElectronic, Ground-state electronic methods (DFT, HartreeFock, coupled-cluster, CI, perturbative approaches), Tight-binding family (TB, xTB, Wannier, SlaterKoster), Excited-state methodology branch (ExcitedStateMethodology, Screening, GW, BSE, TDDFT), Core-hole and many-body electronic methods (CoreHoleSpectra, DMFT)

Key sections: ModelMethodElectronic, DFT, TB, xTB, Wannier, SlaterKoster, ExcitedStateMethodology, Screening, GW, BSE, TDDFT, HartreeFock, CoupledCluster, ConfigurationInteraction, PerturbationMethod, CoreHoleSpectra, DMFT

Force Field ¶

Classical force-field model method branch rooted at ForceField

In scope: ForceField as a ModelMethod subclass, Potential family entry-point used by ForceField contributions, Bridge between model methods and classical interaction potentials

Key sections: ModelMethod, ForceField, Potential

Numerical Settings ¶

Computational parameters: meshes, basis sets, convergence, and discretization

In scope: K-point meshes and line paths for band structures, Real-space meshes and grids, Basis set specifications: plane-wave, APW, atom-centered, Convergence thresholds and maximum iterations, Smearing functions: Fermi-Dirac, Gaussian, Methfessel-Paxton, Force calculation settings

Key sections: NumericalSettings, Mesh, KMesh, KLinePath, KSpace, Smearing, SelfConsistency, ForceCalculations, BasisSetComponent, PlaneWaveBasisSet, APWPlaneWaveBasisSet, AtomCenteredFunction

Outputs ¶

Base output structure and common property definitions

In scope: Outputs section that references ModelSystem and ModelMethod, SCFOutputs with scf_steps for iteration history, PhysicalProperty base class for all computed properties, Property contributions and derivations, SCF convergence checking

Key sections: Outputs, SCFOutputs, PhysicalProperty

Physical Property Backbone ¶

Shared base classes for physical-property types and their common metadata structure

In scope: PhysicalProperty as the common base for computed properties, ErrorEstimate subsection used for uncertainty/error metadata, Abstract/base property families for electronic, Green-function, energy, force, and spectral data, Cross-domain backbone used by specialized output verticals

Key sections: PhysicalProperty, ErrorEstimate, BaseElectronicEigenvalues, BaseGreensFunction, BaseEnergy, BaseForce, SpectralProfile

Electronic Structure Properties ¶

Electronic eigenvalues, band structures, DOS, band gaps, occupancies, and Fermi surfaces

In scope: Eigenvalue hierarchy: BaseElectronicEigenvalues → ElectronicEigenvalues → ElectronicBandStructure, Band structures along high-symmetry paths, Density of states (DOS) profiles, Electronic band gaps (direct, indirect), Orbital occupancies, Fermi surface topology

Key sections: BaseElectronicEigenvalues, ElectronicEigenvalues, ElectronicBandStructure, ElectronicBandGap, DOSProfile, ElectronicDensityOfStates, Occupancy, FermiSurface

Many-Body Properties ¶

Green's functions, self-energies, hybridization, quasiparticle weights, hopping matrices

In scope: Green's function base class and electronic specialization, Self-energies from GW and DMFT, Hybridization functions for impurity problems, Quasiparticle renormalization weights, Hopping matrices from tight-binding, Crystal field splittings in correlated systems

Key sections: BaseGreensFunction, ElectronicGreensFunction, ElectronicSelfEnergy, HybridizationFunction, QuasiparticleWeight, HoppingMatrix, CrystalFieldSplitting

Spectroscopic Properties ¶

Absorption spectra, XAS, and dielectric response

In scope: Spectral profile base class, Absorption spectra from BSE calculations, X-ray absorption spectra (XAS) from core hole calculations, Frequency-dependent dielectric functions (permittivity)

Key sections: SpectralProfile, AbsorptionSpectrum, XASSpectrum, Permittivity

Thermodynamic Properties ¶

Energies, forces, pressure, temperature, and thermodynamic state functions

In scope: Energy hierarchy: BaseEnergy → specific energy types, Free energies: Gibbs, Helmholtz, Force hierarchy: BaseForce → TotalForce, Thermodynamic state variables: pressure, volume, temperature, Entropy and heat capacities, Virial tensor for stress calculations, Hessian matrices for phonon calculations

Key sections: BaseEnergy, TotalEnergy, KineticEnergy, PotentialEnergy, Heat, Work, InternalEnergy, Enthalpy, GibbsFreeEnergy, HelmholtzFreeEnergy, ChemicalPotential, VirialTensor, BaseForce, TotalForce, Pressure, Volume, Temperature, Entropy, HeatCapacity, MassDensity, Hessian