title: Comparative ab initio study of the structures and stabilities of the ethane dication C2H6(2+) and its silicon analogues Si2H6(2+) and CSiH6(2+).
abstract: Ab initio MP2/6-311G and QCISD(T)/6-311G levels as well as Gaussian-2 theory were used to perform a comparative study of the structures and stabilities of the ethane dication C(2)H(6)(2+) and its silicon analogues Si(2)H(6)(2+) and CSiH(6)(2+). Similar to previous HF/6-31G results, our present calculations also indicate that the two-electron three-center (2e-3c) bonded carbonium-carbenium structure 1 is more stable than the doubly hydrogen bridged diborane-type structure 2 by about 12 kcal/mol. For the silicon analogue Si(2)H(6)(2+) the calculations, however, indicate that the 2e-3c bonded siliconium-silicenium structure 8 is about 9 kcal/mol less stable than doubly hydrogen bridged structure 9. Similar results were also computed for carbon-silicon mixed CSiH(6)(2+) dication structures. These studies are in agreement with the more electropositive character of silicon compared to carbon. Possible dissociation paths of the minimum structures were also calculated.
authors.affiliation: Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, University Park, Los Angeles, California 90089-1661, USA. rasul@usc.edu
authors.forename: Golam
authors.initials: G
authors.lastname: Rasul
authors.forename: G K Surya
authors.initials: GK
authors.lastname: Prakash
authors.forename: George A
authors.initials: GA
authors.lastname: Olah