Further developments in the local-orbital density-functional-theory tight-binding method

Quantum-mechanical methods have become increasingly reliable as a complementary tool to experimental research. A variety of methods exist ranging in complexity from semiempirical methods to density-functional-theory (DFT) methods [using either the local-density approximation (LDA) or the generalized-gradient approximation (GGA)] to methods for highly correlated systems (such as multiconfiguration self-consistent field or coupled clusters). Depending on the approximation used, such methods have been effectively applied to a variety of materials and systems.