Electronic structure investigation of the Al4O4 molecule

Structural properties of energetically low-lying isomers of the isolated Al 4O4 molecular system have been investigated by theoretical ab initio techni ques within the Hartree-Fock (HF) and second-order Moller-Plesset (Mp2) fro zen core level of approximation and density functional methods (DFT) employ ing the Becke-3-Pertlew-86 (B3P86) hybrid functional. In total, nine local minima representing six Al4O4 isomers of various spin multiplicities are co mpletely characterised. The two energetically lowest of these stationary po ints, a singlet of planar D-2h and a triplet of cubic T-d symmetry, are fur thermore sifted by considering other choices of exchange (B, B3) and correl ation (LYP, PW91) functionals as well as higher levels of theory (G2/MP2, G 2, and CCSD(T), D-2h only). We report energies, equilibrium geometric param eters, selected harmonic vibrational wavenumbers along with corresponding a bsorption coefficients and compare the different computational approaches. (C) 2000 Elsevier Science B.V. All rights reserved.