On the interpretation of infrared intensities in planar molecular systems

An analytical expression for the atomic charge fluxes in planar molecular systems is given in terms of specific second derivatives of the molecular dipole moments. This, together with previously derived expressions for the atomic charges and point dipoles, offers a formal and rigorous basis for the analysis of IR intensities in planar systems in terms of well-defined quantum-mechanical observables (expectation values). The suggested formalism is consistent with the ECCF model.