Integral approximations for LCAO-SCF calculations

TL;DR: In this paper, the future application of computational tools to chemical, biochemical, and materials problems needs to be critically considered in any new developmental work, for it is important to understand the role of detailed information all the way down to the quantum mechanical level.

TL;DR: Solute-solvent electronic structure interactions of iron porphyrin at very low concentration in dichloromethane (CH2Cl2) liquid solution are reported in this article.

TL;DR: The sc-dRPA method is robust in the sense that it is applicable to all considered molecules, whereas conventional density-functional methods are not applicable to dispersion bonded dimers, and Møller-Plesset perturbation theory of second order erroneously predicts a number of molecules to be unbound and yields completely wrong vibrational frequencies in some cases.

TL;DR: The second-order Moller-Plesset (MP2) method and the linear coupled-cluster model with doubles as examples are discussed as examples to demonstrate the efficiency of this technique in representing the two-electron integrals in a compact form.

TL;DR: In this article, a formalism is developed which allows overlap, kinetic energy, potential energy and electron repulsion integrals over cartesian Gaussian functions to be expressed in a very compact form involving easily computed auxiliary functions.

TL;DR: In this article, an approximate numerical linear dependence among the columns of the two-electron integral matrix and the positiveness of the Coulomb operator are exploited in order to reduce the number of integrals that need to be calculated when a numerical accuracy is given by the machine in use or by the choice of the investigator.

TL;DR: In the multiplicative integral approximation (MIA), two-electron integrals are evaluated using an expansion of a product of two Gaussians in terms of auxiliary functions as discussed by the authors.

TL;DR: A pseudospectral code for general polyatomic molecules has been developed using Gaussian basis functions in this paper, where the water molecule is studied using a 6−31G** basis set and the equilibrium geometry, total energy, first ionization potential, and vibrational force constants are obtained.