Aces2

Aces II is a series of programs for performing ab initio calculations. The package has a high degree of flexibility, and supports many kinds of calculations at a number of levels of theory. The major strengths of the program are in performing calculations using "many-body" methods to treat electron correlation. These approaches, broadly categorized as many-body perturbation theory (MBPT) and the coupled-cluster (CC) approximation, offer a reliable treatment of correlation and have the attractive property of size-extensivity, meaning that energies scale properly with the size of the system. As a result of this property, MBPT and CC methods are ideally suited for the study of chemical reactions.

For complete information see the Aces2 homepage.