The hydrogenated aluminium trimer: a theoretical examination of the formation and interconversion pathways*
Faculty of Chemistry, Wroclaw University, F. Joliot-Curie 14, 50-383 Wroclaw, Poland
Corresponding author: a firstname.lastname@example.org
Revised: 6 August 2007
Published online: 21 September 2007
Five doublet isomers of the Al3H2 cluster lying within a narrow range of 5 kcal/mol, along with the isomerization transition states connecting them, have been located with the coupled-cluster CCSD(T) and DFT methods. The two most stable doublet structures, the C2v planar including the two Hs bound terminally and C1 non-planar showing one H in terminal site and the other in threefold site are found to be essentially degenerate. Although the reaction of Al3 with H2 to yield Al3H2 is found to be significantly exothermic, by 23.5 kcal/mol, this hydrogenation is impeded by a considerable kinetic barrier of 16 kcal/mol. Our result is consistent with the observed lack of reactivity of Aln towards H2(D2) for n=3 under thermal conditions . The quartet Al3H2 isomers are predicted to lie 16–21 kcal/mol higher in energy than the doublet analogues. Further dimerization of Al3H2 to form Al6H4 has also been examined.
PACS: 31.15.Ar – Ab initio calculations / 31.15.Ew – Density-functional theory / 36.40.-c – Atomic and molecular clusters / 36.40.Jn – Reactivity of clusters
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007