Extended tight‐binding quantum chemistry methods

Coupled Cluster methods in quantum chemistry

The Multiconnguration Methods in Quantum Chemistry

The multiconnguration methods are the natural generalization of the well-known Hartree-Fock theory for atoms and molecules. By a varia-tional method, we prove the existence of a minimum of the energy and of innnitely many solutions of the multiconnguration equations, a nite number of them being interpreted as excited states of the molecule. Our results are valid when the total nuclear charge Z ...

Linear-Scaling Methods in Quantum Chemistry

With the introduction of the Schrödinger equation in 1926, it was in principle clear how to describe a molecular system and its properties exactly in a nonrelativistic sense. However, for most molecular systems of chemical interest, the analytic solution of the Schrödinger equation is not possible. Therefore, since 1926, a multitude of hierarchical approximations (some of which are displayed in...

Investigating the Effect of Fullerene on the Basicity of Paraphenylenediamine by using the Quantum Chemistry Methods

In this study, paraphenylenediamine was first bonded to the fullerene and was optimized geometrically by Using the quantum chemistry methods. paraphenylenediamine was examined in the isolated state and in the fullerene-bonded state via carbon atoms. In the theoretical research, the simulation was done by the Gauss View software. Then, the bonding orbital calculation was done by using the NBO me...

Real-space numerical grid methods in quantum chemistry.

Real-space numerical electronic structure methods have lately attracted increasing scientific attention as they are mathematically robust, accurate and well suited for modern, massively parallel computing resources. Despite these significant advantages, numerical quantum chemistry methods are not yet the mainstream approach because they are computationally expensive and can have prohibitive mem...