Studies of depolarized hyper-Rayleigh scattering of an organic molecule

We study the depolarized hyper-Rayleigh scattering of p-nitroaniline (PNA) using an improved technique. The result indicates that the hyperpolarizability tensor of PNA has essentially the characteristics of a rod-like structure, with a single nonvanishing diagonal component β₃₃₃, where the 3-axis corresponds to the polar direction. This is in contrast with previous theoretical calculations, which predicted non-negligible values for some of the off-diagonal components. A plausible explanation of the experimental result is suggested based on a model of the local field correction factors. The result shows that depolarized hyper-Rayleigh scattering may not be very useful in determining the relationship between hyperpolarizability tensor components as previously suggested.