Dependence of approximate ab initio molecular loge sizes on the quality of basis functions

Size and shape parameters for the core, bonding, and lone electron pairs of the ten-electron hydrides (CH₄, NH₃, H₂O, HF) were determined from ab initio MO wave functions using various Gaussian basis sets. The fundamental features of approximate electron pair loge representation are somewhat more sensitive to the quality of the basis functions than the molecular total energy. The total size of the molecular electron distribution is less affected by basis set variations than its components: the core, bonding, and lone pair sizes. There is an apparent tendency to “preserve” the total size of molecular distribution.