Pycc
PyCC is a simple, Python-based, reference implementation of the coupled cluster method of ab initio quantum chemistry.
Install / Use
/learn @CrawfordGroup/PyccREADME
PyCC
A Python-based coupled cluster implementation. Current capabilities include:
- Spin-adapted CCD, CC2, CCSD, CCSD(T), and CC3 energies
- Triples-drivers for various approximate triples methods
- RHF-CC2 and CCSD and densities
- EOM-CCSD
- Real-time (RT) CC2, CCSD, and CC3 with a selection of integrators
- GPU implementations for multiple methods
- Single- and mixed-precision arithmetic
- PAO-, PNO-, and PNO++-CCSD energies RT-CC
Future plans:
- Linear and quadratic response functions
- CC2 and CC3 excited states
- Analytic gradients
Notes on PNO-CC: https://github.com/JoseMadriaga/Notes/blob/main/LocalCCSD.pdf
This repository is currently under development. To do a developmental install, download this repository and type pip install -e . in the repository directory.
This package requires the following:
Optional packages:
Authors
T. Daniel Crawford, Benjamin G. Peyton, Zhe Wang, Jose Madriaga, Aparna Krishnan
Copyright
Copyright (c) 2026, T. Daniel Crawford
Acknowledgements
Project structure based on the MolSSI's Computational Molecular Science Python Cookiecutter Version 1.5.
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