Origin and role of rehybridization moments in determining infra-red intensities

Abstract

Bond moment constants calculated from infra-red band intensities are compared with theoretical estimates calculated by the CNDO (complete neglect of differential overlap) method taking the dipole moment contribution of hybird orbitals into account. Support is obtained for the suggestion by Steele and Wheatley that a rehybridization moment contributes to the intensity of certain bond-bending vibrations. The theoretical model developed is illustrated by calculations on the out-of-plane bending vibration of benzene and on the bending vibration of hydrogen cyanide.