The Influence of Asymmetric Charge Transfer on IR Spectra of Excited Quadrupole Molecules

The influence of symmetry breaking caused by charge transfer in excited quadrupole molecules of the D-π-A-π-D or A-π-D-π-A type, where A and D are the electron-acceptor and electron-donor groups, respectively, on spectra of characteristic vibrations is investigated. Types of possible changes in IR spectra with increase in molecule's asymmetry are classified within the earlier developed theory of symmetry breaking and its manifestation in nonstationary IR spectra. Physical interpretation of the revealed trends is presented, and the latter are compared with currently available experimental data.