Ab initio calculations of the π-electron structures of aniline by the valence-bond method

Abstract

Ab initio valence bond calculations of the π-electron energy levels, π-electron densities and bond orders for aniline have been carried out on the basis of the complete set of non-polar and polar structures. The atomic orbitals have been assumed to be Slater orbitals. The multiple exchange integrals have been taken into account completely by the orthogonalization of the π-atomic orbitals. From the difference of the distribution of the eight π-electrons to the nitrogen atom and the benzene ring, the resonance structures have been divided into two sets: C₆H₅(6)NH₂(2) set and C₆H₅(7)NH₂(1) set. The influences of the substituent on the benzene ring in each set have been compared with benzene and with the benzene negative ion. The interactions between the two sets have been calculated and the effects of these on the molecular properties are discussed.