Gaussian-Type Functions for Polyatomic Systems. II

Abstract

The use of a linear combination of Gaussian-type orbitals (CGTO), instead of an individual Gaussian-type orbital (GTO), as a unit of basis functions for large-scale molecular calculations, is discussed. A systematic construction of the CGTO basis functions is attempted and the results for the atoms from Li through Ar are reported.

Difficulties in the calculation of electron spin resonance parameters using density functional methods

“…This set is a [ 7s6p] contraction ofthe ( II s7p) basis of Huzinaga [22] augmented by two d polarization functions. The van Duijneveldt and the IGLO-III basis set should be of similar quality.…”

Calculation of Potential Energy Surfaces for HCO and HNO Using Many-Body Methods

“…The integrals over atomic functions were computed using Dunning's 4s3p contraction of Huzinaga's 9s5p primitive basis set 34 for first-row atoms and Dunning's scaled (=1.2) 3s contraction of Huzinaga's 4s primitive set for hydrogen. In the formyl radical study, a single set of d-type (Gaussian) polarization functions augments the atomic basis sets for carbon and oxygen, with exponents 0.75 and 0.85, respectively.…”

A group increment scheme for infrared absorption intensities of greenhouse gases

“…[24][25][26] The MP2 method was chosen rather than a density functional theory (DFT) approach, for example B3LYP, because while the B3LYP method may fortuitously yield harmonic frequencies that are closer to the experimental fundamental vibrational frequency compared to MP2, it is our experience that MP2 is superior in predicting the IR intensities. 27,28 This is explained by the well known fact that DFT methods generally do not describe the diffuse part of wave functions reliably, and electrical properties such as the dipole moment, dipole derivatives, polarizabilities, etc.…”