Tang Au‐Chin

Electronic structures of multi-decker transition metal sandwich complexes

The electronic structures of multi-decker transition metal sandwich complexes are discussed according to the structure rules for transition metal heterocarboranes. A series of skeletons of the structures Fe2C5(D5h), Ni2C5(D5h), V2C6(D6h), Co2C6(D6h), and Fe2C4(D4h) are calculated using the EHMO method. The calculated results show that the number of valence bonding orbitals (VBO) can vary as the distance between the metal atoms in the metalocenes is increased. This fact can be used to explain the number of valence electrons (VE) in triple-decker sandwich complexes. The conclusions are proved and discussed through a theoretical analysis of the electronic structures of such complexes and through EHMO calculations for actual compounds containing 29–34 valence electrons.

Ab initio study on the structure and stability of hypervalent molecules: CLi5, CLi6 and related species

Abstract The geometrical structures of CLi5, CLi6 and related species were optimized using the HF, MP2 and DFT methods with the 6-31G* basis set. We have calculated and discussed the stabilities of these perlithiated molecules towards possible dissociation reactions. Results show that the electron correlation effects on the dissociation and atomization energies are very important. Finally, reliable and reasonable dissociation and atomization energies are obtained. For CLi6, the theoretical value is also in good agreement with Kudos recent experimental value.

On the polycondensation reaction of Aa-BbCc type

SummaryThe curing theory for polycondensation reaction of Aa-BbCc type is investigated in detail to give gelation condition explicitly. Furthermore, a recursion formula for evaluating the polymer moments is obtained. This formula is suitable for both pre-gel and post-gel.

Flory-Stockmayer distribution and scaling study

Abstract By means of the Flory-Stockmayer distribution, the critical behavior of the kth radius near the gel point is investigated. As a direct result, a scaling law associated with the kth radius is deduced.

THEORETICAL METHOD OF LIGAND FIELD THEORY AND ITS APPLICATION

It has been more than fifty years since the ligand field theory made its appearance [1,5] . It was initiated in 1931 when Bethes crystal field theory was proposed. The theory of complex spectra for atoms contributed by Racah [6] has had an important effect on the development of ligand field theory as it has affected that of nuclear and elementary particle theories. In this article, we shall try to give a brief review on the extension of irreducible tensor method to ligand field theory, which has been performed by Tang and his collaborators [7–14] .