VBDFT(s) - a semi-empirical valence bond method: Application to linear polyenes containing oxygen and nitrogen heteroatoms

A semi-empirical valence bond (VB) method, VBDFT(s), is applied to the series of linear polyenes with heteroatoms CM -1HMO, CM - 2HM - 2O2, CM - 1HM + 1N, and CM - 2HMN2 (M = 4-26). The computational results show that the VBDFT(s) method, which was first applied to linear polyenes, is also suitable for treatment of linear polyenes with polar bonds. Properties such as the wavefunction, extent of delocalization, the resonance energy, and the energy additivity are discussed.