Contracted Gaussian basis sets for molecular calculations. I. Second row atoms, <i>Z</i>=11–18

TLDR

Contracted Gaussian basis sets for second‑row atoms (Z = 11–18) and the ions P⁻, S⁻, Cl⁻ are derived from uncontracted (12,8) and (12,9) sets. The paper tabulates a hierarchy of basis sets to enable convergent molecular calculations and assess property reliability. The authors derive contracted 3p Gaussian functions from calculations on Na and Mg atoms, and when needed split an uncontracted Gaussian into two contracted functions to prevent energy loss. The resulting basis sets span minimal to triple‑zeta for the 3p orbital, with double‑zeta for the remaining orbitals.

Abstract

Contracted Gaussian basis sets for molecular calculations are derived from uncontracted (12,8) and (12,9) sets for the neutral second row atoms, Z=11–18, and for the negative ions P−, S−, and Cl−. Calculations on Na...2p63p, 2P and Mg...2p63s3p, 3P are used to derive contracted Gaussian functions to describe the 3p orbital in these atoms, necessary in molecular applications. The derived basis sets range from minimal, through double-zeta, to the largest set which has a triple-zeta basis for the 3p orbital, double-zeta for the remaining. Where necessary to avoid unacceptable energy losses in atomic wave functions expanded in the contracted Gaussians, a given uncontracted Gaussian function is used in two contracted functions. These tabulations provide a hierarchy of basis sets to be used in designing a convergent sequence of molecular computations, and to establish the reliability of the molecular properties under study.