Electronic Structure
These documents define the physical electronic-structure objects used by the framework, independently of machine-learning features and code-specific storage formats.
Documents
| Document | Scope |
|---|---|
| Notation and Conventions | Symbols, indices, object types, spin conventions, units, and periodic normalization shared by the electronic-structure documents. |
| Kohn–Sham Density Functional Theory | Born–Oppenheimer electronic problem, spinor Kohn–Sham DFT, density operators, occupations, total energy, and forces. |
| Periodic Systems | Translation symmetry, Bloch states, cell normalization, Brillouin-zone averages, and Fourier conventions. |
| Localized Atomic-Orbital Basis | Nonorthogonal LCAO matrices for \(\mathbf H\), \(\mathbf S\), \(\mathbf D\), and \(\mathbf n\), including finite and periodic systems. |
| Plane-Wave Basis | Plane-wave normalization and reciprocal-space matrices for the same electronic objects. |
| Auxiliary-Basis Expansion and Projection of Density | Auxiliary-basis density coefficients, projection from LCAO density matrices and real-space scalar fields, and unit-cell folding for periodic systems. |
| Pseudopotentials and Effective-Core Operators | Norm-conserving pseudopotentials, effective ionic operators, model core densities, and relativistic content. |
| Projector-Augmented-Wave Method | PAW transformation, auxiliary and all-electron objects, projector density matrices, and one-center reconstruction. |
| Hubbard U Correction | Simplified rotationally invariant DFT+\(U\), correlated-subspace occupation matrices, and the resulting energy and Hamiltonian corrections. |
| Fixed Spin–Orbit Operators in an LCAO Basis | Density-independent fully relativistic nonlocal SOC, its unique spin-traceless definition, projector-centered LCAO contraction, and learning decomposition. |