Dispersion of the first hyperpolarizability of an azulenic donor-acceptor chromophore

The first hyperpolarizabilities ((beta) ) of an azulenic donor-acceptor chromophore at different wavelengths were measured by a tunable wavelength hyper-Rayleigh scattering (HRS) experiments. The (beta) values measured at different wavelengths are used to investigate the dispersion relation of one-dimensional charge transfer organic chromophores. The validity of the well known un-damped two-level model and some modified models which include the damping and the vibronic effects are discussed.