Basis set dependence of molecular information channels and their entropic bond descriptors

Information channels from SCFMO calculations using different basis sets and their entropic bond descriptors are compared within the orbital communication theory. In this information-theoretic (IT) treatment of communications between basis functions the overall covalency and ionicity bond components reflect the average communication noise and information flow, respectively, in the resolution level specified by the adopted set of basis functions. The basis-set dependence of the orbital conditional probabilities and their entropic descriptors of the information covalency/ionicity content is explored. Compared to theminimum set chi of the occupied atomic orbitals of the separated constituent atoms, the extended basis sets of Gaussian orbitals and/or their formal contractions generally give rise to a higher IT-covalency and lower IT-ionicity descriptors of the system chemical bonds. In the augmented set case, chi(aug.) = (chi, psi), containing the polarization function complement psi of chi, the use of only chi -> chi communications is advocated in a semi-quantitative chemical interpretation of the IT bond indices. The maximum-overlap criterion is used to transform the general (orthonormal) extended basis xi to its semi-augmented form (chi) over tilde (aug.) = (xi) over tilde = ((chi) over tilde, (psi) over tilde), in which (chi) over tilde approximate to chi and (psi) over tilde approximate to psi , which facilitates the near minimum basis set interpretation of bond descriptors and extraction of communications involving the polarization functions (psi) over tilde. A similar transformation using the minimum information distance criterion can be