A MOLECULAR ORBITAL TREATMENT OF ACETYLENE INCLUDING ALL ELECTRONS∗ELECTRONS^{*}

$^{*}$Supported by the National Academy of Sciences and the National Science Foundation.Author Institution: Department of Chemistry, Indiana University“The Roothaan SCF procedure has been applied to acetylene, taking into account all 14 electrons of the molecule. The three- and four-center integrals involving the ls orbitals of the carbons have been neglected, and all other multicenter integral have been evaluated by the Mulliken approximation. The calculated ionization potential, as well as the wave-length of the first $\pi \to \pi^{*}$ transition, are in fair agreement with the experimental values. The results of the electron population analysis are also in agreement with experiment and with the current views on hybridization.