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The analysis presents a theoretical study on the assembly and stabilization of the magic cluster, [Al.sub.4][N.sup.-] into molecular systems in sandwich-like forms. The results show that this cluster can also be used as a new superatom due to its high structural and electronic integrity.

A systematic density functional theory (DFT) calculations is performed on the stabilities and electronic properties of two different structures [Csub.58][X.sub.18] and [C.sub.58][X.sub.1], where X = H, F, and Cl. It is seen that the large energy gaps between the highest occupied molecular orbitals and the lowest unoccupied molecular orbital and the aromatic character possess high stabilities.

A series of multiply N-confused porphyrins and their Zn and Cu complexes are investigated by using density functional theory (DFT) and ZINDO/SOS methods. The findings demonstrate that the multiply N-confused results have shown that the one-photon absorption (OPA) spectra of multiply N-confused porphyrins, along with their metal complexes and derivatives are promising molecules, which can be assembled series of materials with large two-photon absorption (TPA) cross sections.

A series of ferrocenyl derivatives with TCF-type acceptors are designed, and their electronic structures and one- and two-photon absorption properties are investigated. Results reveal that ferrocenyl derivatives with TCF-type acceptors are promising candidates for two-photon absorptions (TPA) materials.

The characteristics of antiaromatic ring [pi] multi-hydrogen bonds {[H.sub.2]O}[.sub.n] - [C.sub.4][H.sub.4] (n = 1, 2) complexes are studied. One [H.sub.2]O forms a [pi] H-bond with [C.sub.4][H.sub.4] in two ways, one strong pi H-bond part is always accompanied by another H-bond part which is either a weak [pi] H-bond or [pi]-type H-bond.

The stable structures, energies, and electronic properties of neutral, cationic, and anionic clusters of Al(sub n) (n=2-10) are studied and show that the optimized structure of the clusters are more stable than corresponding ones previously reported and the stability has an odd/even alternation phenomenon. Studies on the structures of the Al(sub n)O (n=2-10) clusters show that oxygen is absorbed at the surface or inserted between Al atoms.

The radical-radical reaction between the ketenyl radical (HCCO) and nitrogen dioxide (NO2) played a very important role in atmospheric and combustion chemistry. The result can lead to a deep understanding of the mechanism of the title reaction and can be helpful for understanding NO(sub x) combustion chemistry.

A detailed theoretical study is carried out for the unknown HCO/HOC + C(sub 2)H(sub 2) reactions at the CCSD(T)/6-311G(2d,p)//B3LYP/6-311G(d,p)+ZPVE, Gaussian-3//B3LYP/6-31G(d), and Gaussian-3//MP2(full)/6-31G(d) levels. For the HCO/HOC + C(sub 2)H(sub 2) reaction, both the most feasible C-addition channel and the slightly less competitive H-donation channel lead to P(sub 1) C(sub 2)H(sub 3) +CO.

The computational study of the complex singlet potential energy surface for the reactions of CN with NO(sub 2) including 9 minimum isomers and 10 transition states is illustrated. The study indicates that the title reaction proceeds mostly through singlet pathways and also gives an understanding on the mechanism of the title reaction and is helpful for understanding NO(sub 2)-combustion chemistry.

The multichannel reactions, HOCl + F -> products and HOBr + F -> products are investigated using the dual-level direct dynamics method. Results reveal that for the F + HOCl reaction, the reaction occurs exclusively through the hydrogen abstraction, while both hydrogen and bromine abstractions are involved in the F + HOBr reaction.