LCAO Self-Consistent Field Calculation of the Twisting Frequency and π-Electron Energy Levels of Allene

Abstract

The twisting frequency of allene is computed by the nonempirical method of antisymmetrized products of molecular orbitals in self‐consistent field LCAO approximation, as applied to the four unsaturation electrons of the molecule, molecular orbitals for these electrons being taken as linear combinations of 2p Slater atomic orbitals. By comparison with a previous calculation by the same method on ethylene, the ratio of the twisting frequency of ethylene to the twisting frequency of allene is computed to be 1.7, sensibly independent of the effective charge in the atomic orbitals, which is the only extrageometrical parameter entering the theoretical calculations. The first ionization potential of allene is predicted to be 10.4 ev and the mean of the first allowed singlet electronic absorption band and the corresponding triplet is predicted to lie at 5.1 ev.