DENSITY-FUNCTIONAL THEORY (DFT) AND AB-INITIO INVESTIGATIONS OF THE ELECTRONIC AND MOLECULAR-STRUCTURES OF THE MONOMER AND THE DIMER OF TRIMETHYLALUMINUM

The electronic and molecular structures of the monomer and dimer of tr imethylaluminium have been studied using density functional theory and ab initio MP2 method. The optimized geometry of the monomer Al(CH3)(3 ) is of C-3h symmetry, whereas that of the dimer [Al(CH3)(3)](2) conta ins a carbon-bridged four-membered ring structure with C-2h symmetry. The hydrogen-bridged six-membered ring structure is found to be unstab le. The calculated dimerization energy for the four-membered ring stru cture is 78 kJ/mol, in close proximity to the experimental value of 85 .27 kJ/mol.