THE ELECTRONIC STRUCTURE OF $C_{4}{^{\ast}}$
Loading...
Date
1984
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Electronic structure calculations were carried out for the $C_{4}$ molecule in the linear $(^{3}\Sigma^{-}_{g})$ and rhombus (bicylic, $^{1}A_{g}$) configurations. The calculations used double-zeta (DZ) and DZ plus polarization (DZP) basis sets, and were carried out at the SCF (RHF), MCSCF, single-reference CI, and multireference CI levels. The geometries of the two structures were optimized at the MCSCF level, and the resulting bond lengths are greater by $0.03 - 0.09 {\AA}$ than those optimized by Whiteside $et al.^{1}$ at the SCF (UHF) level. The relative energies of the two structures are very sensitive to the basis set used and, to a lesser degree, to the type of wave function. The $D_{2}$ basis strongly favors the linear structure, but the energies of the two structures are comparable when the DZP basis is used.
Description
$^{1}$ R.A. Whiteside, R. Krishnan, D.J. Defrees, J.A. Pople, and P.v.R. Schleyer, Chem. Phys. Letters 78, 538 (1981). $^{\ast}$ Supported in part by the U.S. National Science Foundation under Grant CHE-8219408 and in part by Jilin University, Changchun, China.
Author Institution: Institute of Theoretical Chemistry, Jilin University; Department of Chemistry, Ohio State University
Author Institution: Institute of Theoretical Chemistry, Jilin University; Department of Chemistry, Ohio State University