A HEI PHOTOELECTRON-SPECTRUM OF THE [AL(CH3)(3)](2) DIMER

The HeI photoelectron spectrum (PES) of the [Al(CH3)(3)](2) dimer is r ecorded for the first time. To assign the PES bands, an ab initio SCF MO calculation for the dimer has also been performed. The four splitti ng peaks of the first PE band are respectively designated to electron ionization of the four frontier 8b(u), 13a(g), 7b(g) and 7b(u) orbital s of the dimer. They originate from the recombination of the two HOMO (5e') of the two monomers in the forming of the dimer. That is to say, during the formation of the dimer from the two monomers, the reductio n of molecular symmetry (from the C-3h symmetry of the monomer to the C-2h, symmetry of the dinner) leads to the undergeneration of the dege nerate orbitals. (C) 1997 Elsevier Science B.V.