Quasielastic light scattering from solutions of lollipop‐shaped particles

An expression is derived for the field correlation function of the light scattered from a solution of lollipop‐shaped particles. Such particles are a tractable model of certain bacteriophages. They are assumed to consist of an ellipsoidal head containing optically anisotropic scattering material and a tail which does not scatter. Because of the tail, Brownian rotational movement occurs around a center of rotational friction which is at a distance r 0 from the center of the head. The dependence of the field correlation function C (τ) on the rotational diffusion coefficient D R is given by the factor Σ l B l exp[− l ( l + 1) D R τ]. It is shown that the tail causes the coefficients B l to be different from zero for all values of l . Therefore, C (τ) contains a term proportional to exp(−2 D R τ), which is not present when r 0 = 0. We give plots of B l for various combinations of parameters. It turns out that dynamic light scattering may be used to measure r 0 .