Release notes

[2.8.0] - 2025-09-04

Five years of work: new transition-state methods, more potential interfaces, and a Meson build that runs on Linux, macOS, and Windows.

Major features

  • RO-NEB-CI: climbing-image NEB with a rotating-orbit refinement for locating complex transition states. (#239)

  • Machine-Learned Potentials with metatomic: Integrated full support for metatomic potentials, enabling high-performance simulations with current models from the metatensor ecosystem. (#201)

  • Expanded Potential Interfaces: Drastically increased interoperability by adding direct interfaces for a wide range of popular computational chemistry packages:

    • NWChem: High-performance, socket-based interface for large-scale calculations. (#244)

    • ORCA: Direct support for the versatile and efficient ORCA quantum chemistry program.

    • AMS: Interface for the Amsterdam Modeling Suite (ADF, BAND, DFTB).

    • XTB: Fast and reliable calculations using the GFN-xTB semi-empirical tight-binding methods.

    • ASE: General-purpose interface to any calculator supported by the Atomic Simulation Environment (ASE).

  • Input Validation and Schema: A Pydantic schema for all configuration files. Automatic input validation, clearer error messages, and a base for auto-generated documentation.

  • ZBL Universal Potential: Added support for the Ziegler-Biersack-Littmark (ZBL) universal screening potential, ideal for simulating high-energy collision cascades and ion-implantation effects. (#241)

Enhancements

  • Nudged Elastic Band (NEB) Enhancements: The NEB module has received significant upgrades for flexibility and performance:

    • Endpoint Minimization: Added an option to pre-optimize the initial and final states of a NEB path, improving convergence and accuracy. This feature is fully compatible with restarts. (#221)

    • Custom Initial Paths: Users can now provide a custom series of intermediate structures to initialize a NEB calculation, offering greater control over the reaction pathway.

    • Dual Optimizers: Enabled the use of different optimizers for the climbing image versus the regular images in a CI-NEB calculation.

    • Energy-Weighted Springs: Implemented energy-weighted dynamic springs, improving stability and performance for reaction paths with high energy barriers.

Build and installation

  • Modernized Build System with Meson: The entire project has been ported to the Meson build system. One build on Linux, macOS, and Windows. The same tree is the base for a later pure-Python eon-server package. (#124)

  • Cross-Platform CI & Support:

    • Continuous Integration (CI) pipeline, automatically testing builds and features across Linux, Windows, and macOS (Intel & Apple Silicon ARM).

    • Official support for Apple Silicon (M1/M2/M3) machines.

    • The command-line interface is now fully compatible with Windows environments.

  • Dependency Management: Added official support for Conda and Mamba, allowing for simple, one-command environment setup.

  • High-Performance Logging: Replaced the internal logging system with spdlog for asynchronous, configurable, and more informative output with minimal performance overhead.

  • Code Modernization:

    • The C++ backend has been upgraded to the C++17 standard.

    • Adopted modern C++ features like smart pointers and the <filesystem> library for safer memory management and platform-independent file I/O.

    • Enforced consistent code style and formatting across the entire codebase.

Documentation

  • Added documentation for the Nudged Elastic Band (NEB) module, covering theory, keywords, and practical examples.