Atomic basis functions for molecular electronic structure calculations

Abstract

Electronic structure methods for accurate calculation of molecular properties have a high cost that grows steeply with the problem size, therefore, it is helpful to have the underlying atomic basis functions that are less in number but of higher quality. Following our earlier work [Chem. Phys. Lett. 416, 116 (2005)] where general correlation-consistent basis sets are defined, for any atom, as solutions of purely atomic functional minimization problems, and which are shown to work well for chemical bonding in molecules, we take a further step here and define a new kind of atomic polarization functionals, the minimization of which yields additional sets of diffuse functions that help to calculate better molecular electron affinities, polarizabilities, and intermolecular dispersion interactions. Analytical representations by generally-contracted Gaussian functions of up to microhartree numerical accuracy grades are developed for atoms Hydrogen through Nobelium within the four-component Dirac-Coulomb theory and its scalar-relativistic approximation, and also for Hydrogen through Krypton in the two-component nonrelativistic case. The convergence of correlation energy with the basis set size is studied, and complete-basis-set extrapolation formulas are developed.

Ratiometric Detection of ATP by Fluorescent Cyclophanes with Bellows‐Type Sensing Mechanism

“…Molecular geometries of complexes were optimized by a parametrized model involving dispersion interactions starting from a limited set of conformations from molecular dynamics . The geometry of the complex with the lowest energy was further optimized by MP2 method by using the L1 basis set (Figure c) . According to the calculations, the adenine ring intercalates with both pyrene rings and forms hydrogen bonds with the side chains—amine spacers.…”

Methane Over‐Oxidation by Extra‐Framework Copper‐Oxo Active Sites of Copper‐Exchanged Zeolites: Crucial Role of Traps for the Separated Methyl Group

“…PBE yields good structural parameters for copper‐oxo active sites in copper‐exchanged zeolites. For these calculations, we employed AE basis sets labelled previously as L1 and of double‐ζ‐polarized quality for the large component and appropriate kinetically balanced basis sets for the small components [54–55] . The Al and Si atoms were described with 15s11p2d (contracted to 4s3p1d) while the C and O atoms were described with 12s7p2d (contracted to 3s2p1d).…”

Small helium clusters formation

“…This basis length is quite suitable for estimates and discussions presented below, because the increasing its length does not give visible changes. To get more accurate calculations it is helpful to use the atomic basis sets from reference .…”