Theoretical study of the mechanisms of ethylene polymerization with metallocene-type catalysts

Article Abstract:

Research was conducted to examine the three possible mechanisms of ethylene polymerization in the presence of zirconocene catalysts. The density functional theory method with gradient-corrected exchange-correlation functions and full geometry optimization at that level was used. Of the three mechanisms, only the stepwise backside (BS) and frontside (FS) mechanisms seemed competitive. Results confirm previous results showing the critical role of agostic interactions along the reaction paths and the significant preference for FS with respect to BS insertion.

Transition metals, Polymerization, Metallocenes, Ethylene

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Modeling of uranyl cation-water clusters

Article Abstract:

The model potential for uranyl cation-water clusters, one including polarization effects explicitly and charge-transfer effects implicitly, and the other including these two effects explicitly are derived from ab initio calculations on [UO2(H2O)](super 2+). The model with the explicit charge-transfer term reproduces accurately the ab initio geometries and energies of small clusters with containing up to five water molecules.

Analysis, Cations, Charge transfer, Polarization (Electricity), Atomic properties

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Derivation of an optimized potential model for phase equilibria (OPPE) for sulfides and thiols

Article Abstract:

Research into the development of a force field for sulfides and thiols is presented. An extension of the anisotropic united atoms model is suggested for thiols and sulfides.

Sulfides, Thiols

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