Analysis of the electron pair density for the ground state of carbon dioxide

Abstract

The centre-of-mass or extracule and relative distance or intracule electron pair densities for the ground state of CO2 have been analysed by means of the radial, longitudinal and transverse reduced distribution functions. Calculations demonstrate that the independent-atom model (IAM) accounts for the chief characteristics of the distributions. The basis set dependence of the pair densities is illustrated by the moments of the distributions. Calculations with the 3-21G, 6-31G and 6-31G* basis sets show that augmenting the number of primitives of the various shells has a more profound effect than the addition of polarization functions. Finally analysis of increment electron-pair densities reveals that the 6-31G* basis favours small and intermediate distances with the respect to both the 3-21G and 6-31G basis set.