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To investigate the elementary events of the decomposition of transition metal complexes, a density functional study of the systems Cr(C6H6)2 and Cr(C6H6) as well as their corresponding cations, has been carried out. The results give a low bond energy (0.36 eV) for the neutral Cr(C6H6) compound while the binding energy of the cation Cr(C6H6)⁺ is much higher (1.84 eV), in good agreement with previous theoretical and experimental studies. Concerning the dissociation of Cr(C6H6)2, the first process (dissociation of the first ligand) needs much higher energy than the second one, and depends on the intersystem crossing relaxation (ISC) of the intermediate Cr(C6H6) compound. Taking into account the ISC process, the three-body decomposition occurs at 3.40 eV, in good agreement with recent experimental results. In the case of the Cr(C6H6)2⁺ dissociation, both processes (with and without ISC) may be available from recent experimental works. Our theoretical results reproduce very well the values corresponding to both ways of decomposition.

The inhibitive effect of 3-amino 1,2,4-triazole (ATA) on the pitting corrosion of copper induced by sulphate ions was compared to that obtained with benzotriazole (BTAH) and 1-hydroxybenzotriazole (BTAOH) and to previous results obtained in chloride media. It was concluded that the inhibitive action of these compounds towards pitting corrosion was dependent on the aggressive species. For BTAH and BTAOH, the inhibitive efficiency was greater towards pitting induced by sulphate than towards pitting induced by chloride which was explained by referring to the surface area covered by the organic molecules and to the size of the aggressive species. For ATA, an opposite behaviour was observed and was explained by quantum chemical calculations. First, the binding energy between clusters of Cu+ions and Cl−was much weaker than that between clusters of Cu+ions and SO42−. Secondly, the adsorption of Cl−on ATA linked to copper ions was more favourable than its adsorption on copper oxide. Moreover, the sulphate ion had a larger adsorption energy on copper ions than on ATA linked to copper ions.

Cu thin films were deposited in the temperature range 100–180°C using the title precursor by photo-MOCVD. The ultraviolet (UV) photons facilitate a clean removal of the ligands. Consequently, the growth rate is slightly increased under irradiation and the morphology and the film resistivity is improved.

Revised values of core pseudopotential parameters are presented together with optimized PS-31 G valence basis sets for atoms from Li to Ca and from Ga to Kr. Studies with more than thirty test molecules indicate a very good agreement with 6-31 G results for atomization energies, geometries, dipole moments and force constants.

An analysis of atomic charges is presented for simple alkanes. Basically, Mulliken's scheme is followed, except for the partitioning of CH overlap populations. This achieves a relative ordering of atomic charges which is independent of the basis sets used in abinitiocalculations. The absolute magnitude of atomic charges, however, is basis set dependent. Extensive geometry and scale factor optimizations yield the following results (in 10−3 e units) for the carbon net charge in ethane: 69.4 (STO-3G), 55.1 (STO-3G + CI), 42.8 (4-31G), and 37.8 (4-31G + CI). It appears that charge analyses converge toward the empirical result, 35.1 × 10−3 e, provided they are carried out after configuration interaction involving reasonably large optimized basis sets.