ELECTRONIC STRUCTURE OF POLYHEDRAL ALKANES
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Date
1985
Journal Title
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Publisher
Ohio State University
Abstract
The electronic structure and bond distances for the three polyhedral alkanes, tetrahedrane ($C_{4}H_{4}$), cubane ($C_{8}H_{8}$), and dodecahedrane ($C_{20}H_{20}$) have been studied with Hartree-Fock-Roothaan molecular orbital wavefunctions. Contracted Gaussian (9s5p/4s), [4s3p/2s] basis sets of atomic orbitals were used. These are somewhat superior to double-zeta or split-valence basis sets, but lack polarization functions. Full use was made of the symmetry of the molecules. Both the CC and CH bond distances were optimized. As expected, $C_{4}H_{4}$ has the shortest CC bond distances, and $C_{8}H_{8}$ has the longest. The CH bond distances varied also, but to a somewhat smaller extent. All (vertical) valence ionization potentials were computed, both from the neutral molecule orbital energies (Koopmans’ Theorem) and from calculations of all of the positive-ion energies ($\Delta$SCF method). Relaxation energies of 0.1 eV were typical. The majority of the ion states are spatially degenerate, and the resulting Jahn-Teller splittings should have a large effect on the photoelectron spectra.
Description
Author Institution: Department of Chemistry, The Ohio State University; Department of Chemistry, The Ohio State University; Department of Chemistry, The Ohio State University