Intensities of Electronic Transitions in Molecular Spectra II. Charge‐Transfer Spectra

Two related types of high intensity molecular spectra are discussed. These are designated as charge‐resonance spectra and charge‐transfer spectra. In the molecular orbital approximation, both these types usually involve transfer of one electron from a bonding to the corresponding antibonding molecular orbital. In the atomic orbital approximation, charge‐resonance spectra involve a transition from a symmetrical to a corresponding antisymmetrical state, the wave function of each of these two states being a linear combination of two wave functions representing two hypothetical states of a molecule that are equivalent or nearly so but different in charge distribution. Charge‐transfer spectra in the atomic orbital approximation involve a transition from a state having a non‐ionic to one having an ionic wave function (N→V transition). Theoretical equations for dipole strengths and f values for both these types are given, in each case calculated according to each of the two approximations. The equations are very...