ab initio Cyclic Cluster Model

The ab initio Cyclic Cluster Model (AICCM) program is an object oriented, educational quantum chemical code written in the Python scripting language with C extensions. It depends on the Atomic Simulation Environment (ASE) for calculation setup and makes heavy use of Python modules (NumPy, SciPy, Matplotlib) and LAPACK routines. It is mainly developed by Michael F. Peintinger and Thorsten Claff at the Mulliken Center for Theoretical Chemistry at the University of Bonn (Germany). You can find a full list of contributors in the development section. The aim is to implement the Cyclic Cluster Model (CCM), which directly applies periodic boundary conditions (PBC) to a finite free cluster (corresponding to a non-primitive unit cell), at ab initio level.

Atomic Simulation Environment (ASE)

The Atomic Simulation Environment (ASE) provides Python modules for manipulating atoms, analyzing simulations and visualization and is interfaced by various quantum chemical codes. AICCM is implemented as an ASE calculator.


AICCM is free software! You can redistribute and/or modify it under the terms of the GNU General Public License (GPL) as published by the Free Software Foundation, either version 3 of the License or any later version.


All news, release announcements, feature implementations and events related to AICCM are published in our twitter feed.

AICCM development is currently discontinued. If you plan to include the Cyclic Cluster Model into your quantum chemical program and have questions please do not hesitate to contact Michael Peintinger directly.

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