The Interatomic Potentials Repository Project (IPRP), managed by the National Institute of Standards and Technology (NIST), provides a source for interatomic potentials (force fields), related files, and evaluation tools to help researchers obtain interatomic models and judge their quality and applicability. The NIST IPRP co-evolved with the OpenKIM project and is synergistic to it. The IPRP was founded by Dr. Chandler Becker who serves on the Board of the OpenKIM project.
The IPRP accepts all content as long as it is adequately documented. Most IPRP potentials correspond to parameter files for standard potential forms (such as the embedded-atom method (EAM)). These parameter files work with codes that are designed to read them. In contrast KIM models are more general and include the software implementation of the potential along with the parameters. The OpenKIM project believes that inclusion of the potential implementation is necessary to ensure the reproducibility of simulations. (For example, EAM implementations using different interpolation methods can lead to different results for the same parameter file.)
The portability and reproducibility of KIM models required the development of the KIM API. This ongoing and challenging effort began in 2009 in collaboration with leading developers of interatomic models and molecular simulation codes. At the same time, Dr. Becker expanded the IPRP through a sustained outreach effort. As a result, within several years, the IPRP contained a large number of parameter files (mostly for the EAM potential) for different material systems. This content was later absorbed as "KIM-compliant Models" within openkim.org in coordination with the NIST IPRP and after receiving permission from the original content submitters. The OpenKIM project acknowledges this important contribution to its initial content base. Below you will find a list of those models which were incorporated from the IPRP at that time. In addition, as described below, all OpenKIM content which is also available from the NIST IPRP is associated with a hyper-link to where that content is archived within the NIST IPRP.
The OpenKIM project and the NIST IPRP continue to collaborate and cooperate. The NIST IPRP provides archival storage for content of all types pertaining to interatomic potentials. OpenKIM provides archival storage for KIM-compliant potentials as well as other, non-compliant interatomic potentials. The latter type of potentials are referred to as "external models" within the OpenKIM system and are given KIM IDs to enable citation. In order to make it easy for users to upload their content to both OpenKIM and the NIST IPRP, openkim.org provides a unified upload page. For content uploaded to both the NIST IPRP and OpenKIM, each archive provides a hyper-link to the corresponding content archived in the other. It is the intention of the OpenKIM project to continue working closely with the NIST IPRP to serve the needs of the materials research community.