Recent improved definitions of bond order and valencies are reviewed. Extensive tests of the determination of these properties from ab initio wavefunctions are reported, using prototypical molecules, such as methyl radical, ethylene, acetylene, water and hydrogen fluoride. The extension of these definitions to the unrestricted Hartree-Fock and post Hartree-Fock levels of theory are discussed. The concepts are applied to the study of charge carrier defects in large polyene molecules. Post Hartree-Fock calculations are carried out at the MC SCF level of theory using a complete π active space for the C5H7, C7H9, C9H11 and C11H13 radicals. The fully optimized structures are reported and their electronic properties analyzed in terms of bond orders.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Condensed Matter Physics
- Atomic and Molecular Physics, and Optics
- Surfaces and Interfaces