Two-electron valence indices from the Kohn-Sham orbitals

✍ Scribed by Roman F. Nalewajski; Janusz Mrozek; Artur Michalak

• Book ID: 101253847
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 231 KB
• Volume: 61
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1997)61:3<589::aid-qua28>3.0.co;2-2

✦ Synopsis

The recent Hartree᎐Fock HF difference approach to the chemical valence indices ionic . and covalent , formulated in the framework of the pair-density matrix, is implemented Ž . Ž . within the Kohn᎐Sham KS density functional theory DFT . The valence numbers are quadratic in terms of displacements of the molecular spin-resolved charge-and-bond-order Ž . Ž . CBO matrix elements, relative to values in the separated atoms limit SAL . It is shown that the global valence represents a generalized ''distance'' quantity measuring a degree of similarity between the two CBO matrices: the molecular and SAL. Numerical values for typical molecules exhibiting single and multiple bonds demonstrate that the KS orbitals give rise to these new bond valences in good agreement with both chemical and HF predictions. This KS bond multiplicity analysis is applied to the chemisorption system including the allyl radical and a model surface cluster of molybdenum oxide. It is concluded that the quadratic valence analysis represents a valuable procedure for extracting useful chemical information from standard DFT calculations.