EMPIRE: a highly parallel semiempirical molecular orbital program: 2: periodic boundary conditions

The increasing role of quantum chemical calculations in drug and materials design has led to a demand for methods that can describe the electronic structures of large and complex systems. Semiempirical methods based on the neglect of diatomic differential overlap (NDDO) approximation (e.g., the MNDO, MNDO/d , AM1 , AM1* , and PMx methods) are important representatives of such approaches. Many of these methods have been implemented in the massively parallel program EMPIRE], which makes the full quantum-mechanical treatment of systems containing 100,000 atoms or more possible.