2003/11/04 by Alberto Grassi, A. Grassi, Giuseppe M. Lombardo +6
Engineering · Materials Science · Physics and Astronomy · #Advanced Chemical Physics Studies #Boron and Carbon Nanomaterials Research #Ion-surface interactions and analysis #physics.atm-clus #physics.chem-ph
paper · pdf · doi:10.1016/j.chemphys.2003.10.001
published as Chem. Phys. 297 (2004) 13
openalex publication_date 2003/11/04 · arxiv created 2004/04/30 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Motivated by solid-state studies on the cleavage force in Si, and the consequent stretching of chemical bonds, we here study bond stretching in the, as yet unsynthesized, free space molecule Si6H6. We address the question as to whether substantial bond stretching (but constrained to uniform scaling on all bonds) can result in a transition from ring current behaviour, characteristic say of benzene at its equilibrium geometry, to localized pi-electrons on Si atoms. Some calculations are also recorded on dissociation into 6 SiH radicals. While the main studies have been carried out by unrestricted Hartree-Fock (HF) theory, the influence of electron correlation has been examined using two forms of density functional theory. Planar Si6H6 treated by HF is bound to be unstable, not all vibrational frequencies being real. Some buckling is then allowed, which results in real frequencies and stability. Evidence is then provided that the non-planar structure, as the Si-Si distance is increased, exhibits pi-electron localization in the range 1.2-1.5 times the equilibrium distance.