pCI is a high-precision relativistic atomic structure software package written in Fortran and designed for use on modern HPC systems. The calculations are based on the configuration interaction method and extendable to utilize many-body perturbation theory (MBPT) or the all-order method to attain even higher accuracy.
pCI is developed and maintained at the University of Delaware. All of its development is done in the GitHub repository under the dev branch.
We welcome all contributions to the pCI software package, including bug fixes, feature enhancements, and documentation improvements. In order to contribute, open an issue or a pull request on GitHub.
Code documentation is hosted at Read the Docs.
If you use pCI, please acknowledge it by citing the main publication listed here:
C. Cheung, M. G. Kozlov, S. G. Porsev, M. S. Safronova, I. I. Tupitsyn, and A. I. Bondarev, pci: A parallel configuration interaction software package for high-precision atomic structure calculations, Computer Physics Communications 308, 109463 (2025).
@article{2025pCI,
title = {pCI: A parallel configuration interaction software package for high-precision atomic structure calculations},
journal = {Computer Physics Communications},
volume = {308},
pages = {109463},
year = {2025},
author = {Charles Cheung and Mikhail G. Kozlov and Sergey G. Porsev and Marianna S. Safronova and Ilya I. Tupitsyn and Andrey I. Bondarev},
}