Imago is an all-electron electronic structure code implementing the OLCAO (Orthogonalized Linear Combination of Atomic Orbitals) method. It applies to a broad range of material systems: crystals, amorphous solids, nanoparticles, molecules, interfaces, and grain boundaries.
Key characteristics:
- All-electron -- no pseudopotentials; core electrons are treated explicitly.
- Periodic boundary conditions -- used throughout, even for non-periodic systems.
- LCAO basis -- wavefunctions expressed as linear combinations of atomic orbitals.
- Orthogonalization -- valence orbitals are orthogonalized to the core, shrinking the secular (eigenvalue) equation.
Imago is the successor to the long-running OLCAO codebase. The method retains its established name; only the code has been rebranded.
See BUILD.md for the production build and the opt-in debugging builds.
Project documentation is in docs/. The design document
chain -- vision, architecture, design, and pseudocode -- lives in
dev/ and is the authoritative description of how and why
the code works the way it does.
See CONTRIBUTING.md for licensing, credit, and
the design chain discipline that governs changes to src/.
Imago is licensed under the Educational Community License, Version 2.0 (ECL-2.0). See LICENSE for the full text and NOTICE for attribution notices that must accompany redistribution.
Copyright (c) 2026 Paul Rulis.
If you use Imago in published work, please cite it. Machine-readable
metadata is in CITATION.cff; GitHub renders it as a
"Cite this repository" panel, and cffconvert will turn it into
BibTeX or other formats.
A DOI will be minted at the first tagged release and added to
CITATION.cff. Until then, cite the repository directly.
Computational Physics Group, University of Missouri--Kansas City.