title: Role of s-p orbital mixing in the bonding and properties of second-period diatomic molecules.
abstract: Qualitative molecular orbital theory is widely used as a conceptual tool to understand chemical bonding. Symmetry-allowed orbital mixing between atomic or fragment orbitals of different energies can greatly complicate such qualitative interpretations of chemical bonding. We use high-level Amsterdam Density Functional calculations to examine the issue of whether orbital mixing for some familiar second-row homonuclear and heteronuclear diatomic molecules results in net bonding or antibonding character for a given molecular orbital. Our results support the use of slopes of molecular orbital energy versus bond distance plots (designated radial orbital-energy slope: ROS) as the most useful criterion for making this determination. Calculated atomic charges and frontier orbital properties of these molecules allow their acid-base chemistry, including their reactivities as ligands in coordination chemistry, to be better understood within the context of the Klopman interpretation of hard and soft acid-base theory. Such an approach can be extended to any molecular species.
authors.affiliation: Scheikundig Laboratorium der Vrije Universiteit, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands.
authors.forename: F Matthias
authors.initials: FM
authors.lastname: Bickelhaupt
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Nagle
authors.forename: William L
authors.initials: WL
authors.lastname: Klemm