Spectrum of light quasielastically scattered from tobacco mosaic virus

We present measurements of the spectrum of light scattered from solutions of tobacco mosaic virus. The spectrum, which is generally not Lorentzian in shape, was measured at a series of angles ranging from 20° to 170° in solutions of 0.02% and 0.04% by weight. We have analyzed this data in terms of a theory which includes the effect on the spectrum of both rotational and anisotropic translational diffusion of rodlike molecules of length L. By calculating the angular dependence of the spectra both in tails and at the line center, it is possible to provide graphically and analytically simple means of estimating the average translational diffusion constant, D̄, and a linear combination of the rotational constant, DR, and the translational anisotropy, D∥-D⊥. We find D̄ = (0.390±0.01)×10-7cm2/sec, and -6.65 (D ∥-D⊥)+0.84DRL2= (3.10±0.30)×10-7 cm2/sec at 25°C for both tobacco mosaic virus solutions.