Mechanical Properties of Nanostructured Materials e-bog

Nowadays, with the improved abilities of computers, molecular modeling has become a powerful technique in computational chemistry with ever-increasing practical interests. At the moment, using effective algorithms along with powerful processors enables us to simulate systems, including thousands of atoms up to several microseconds. However, finding a balance between the computational costs and reliable results still remains a challenge. Two general approaches help us to reveal the behavior of these systems: quantum chemical calculations and molecular mechanics calculations. Quantum mechanics deals with physical phenomena as well as atoms behavior during chemical bonding and falls in the category of modern physics. In this book, two of the most practical quantum mechanics approaches are investigated: density functional theory (DFT) and density-functional tight-binding (DFTB).