QMMMBerechnungen

QMMMBerechnungen, short for Quantum Mechanical/Molecular Mechanics calculations, are computational methods used to study the properties and behavior of molecules and materials. These calculations combine quantum mechanics, which describes the behavior of electrons, with molecular mechanics, which describes the behavior of atomic nuclei. The primary goal of QMMM calculations is to provide a more accurate and detailed understanding of molecular systems by treating different parts of the system with different levels of theory.

In QMMM calculations, the system is divided into two regions: the quantum mechanical (QM) region, where the electronic structure is explicitly calculated using quantum mechanical methods, and the molecular mechanics (MM) region, where the interactions between atoms are described using classical force fields. The QM and MM regions are connected through a boundary region, where the interactions between the QM and MM regions are treated using a linking scheme.

QMMM calculations are widely used in various fields, including chemistry, biology, and materials science. They are particularly useful for studying systems where only a small part of the system is of interest, such as the active site of an enzyme or the defect site in a material. By treating the relevant part of the system with quantum mechanics and the rest with molecular mechanics, QMMM calculations can provide a more accurate and efficient description of the system.

There are several software packages available for performing QMMM calculations, including Gaussian, Q-Chem, and CP2K. These packages provide a range of methods and options for setting up and running QMMM calculations, making them accessible to researchers in various fields. Overall, QMMM calculations are a powerful tool for studying the properties and behavior of molecular systems, providing insights that would be difficult or impossible to obtain using other methods.