GSAS-II
Computing Applications (HPC) BSD-3-Clause (Free)
About
Auto-indexing and Rietveld refinement of powder X-ray and neutron diffraction patterns. Indexes patterns into ranked unit cells with M20/F20 figures of merit and refines structural models (Rwp, GOF, lattice parameters), running headless via the scriptable interface.
Skills
MCP skills available for GSAS-II, callable from AI workflows and the Paramus chat:
- Index Peaks — Auto-index a powder X-ray or neutron diffraction pattern into ranked candidate unit cells using the GSAS-II indexer. Returns unit cells with M20/F20 figures of merit. Runs GSAS-II headless in a Docker container via the BRAIN platform.
- Info — Return capabilities, available methods and metadata for the GSAS-II powder diffraction HPC module on the BRAIN platform.
- Rietveld Refine — Run a GSAS-II Rietveld refinement of a CIF structural model against an observed powder X-ray or neutron diffraction pattern. Returns the weighted profile residual (Rwp), goodness of fit (GOF), refined lattice parameters and a real convergence flag. Runs GSAS-II headless in a Docker container via the BRAIN platform.
Browse the full GSAS-II skill documentation
Citation
Toby, B.H.; Von Dreele, R.B. GSAS-II: the genesis of a modern open-source all purpose crystallography software package. J. Appl. Cryst. 46, 544-549 (2013). DOI:10.1107/S0021889813003531
Frequently Asked Questions
What is GSAS-II?
GSAS-II is a computing applications (hpc) application available in the Paramus App Store. Auto-indexing and Rietveld refinement of powder X-ray and neutron diffraction patterns. Indexes patterns into ranked unit cells with M20/F20 figures of merit and refines structural models (Rwp, GOF, lattice parameters), running headless via the scriptable interface.
Is GSAS-II free to use?
Yes. GSAS-II is distributed under the BSD-3-Clause (Free) license and is available at no cost through the Paramus App Store.
How do I install GSAS-II?
GSAS-II is installed through Paramus Chemistry OS, an on-premise Windows platform for computational chemistry. Open the Paramus App Store in your local installation and select GSAS-II for one-click deployment.
What type of application is GSAS-II?
GSAS-II belongs to the “Computing Applications (HPC)” category in the Paramus App Store. It runs on Paramus Chemistry OS and can also be accessed through Paramus Cloud for supported workflows.
What platform does GSAS-II run on?
GSAS-II runs on Paramus Chemistry OS, a Windows-based on-premise platform that provides local compute power for demanding simulations. It requires a Paramus OS installation with appropriate hardware resources.
Can GSAS-II be automated or integrated with AI workflows?
Yes. GSAS-II is available as part of the Paramus ecosystem which supports MCP (Model Context Protocol) tools for AI-driven automation. This enables integration with large language models and automated research pipelines.
How should I cite GSAS-II in publications?
The recommended citation for GSAS-II is: Toby, B.H.; Von Dreele, R.B. GSAS-II: the genesis of a modern open-source all purpose crystallography software package. J. Appl. Cryst. 46, 544-549 (2013). DOI:10.1107/S0021889813003531