Abstract
Quasielastic light scattering is now a well-established technique for rapid determination of diffusion coefficients from the spectral density of Rayleigh scattered light. Application of a constant electric field in the course of a quasielastic light scattering experiment, a technique termed electrophoretic light scattering (ELS), results in a series of peaks that are Doppler shifted by an amount proportional to the superimposed instantaneous velocity of the molecules. Electrophoretic mobilities, diffusion coefficients, and relative concentrations of each component in a polydispersed system can be determined from a single ELS experiment. A theory for polymer dynamics in the presence of an applied sinusoidal field has also been proposed. The present communication presents data in which the center-of-mass of DNA is studied in the presence of a low frequency sinusoidal field. It is shown that: (1) at very low frequencies the power spectrum is composed of several peaks Doppler shifted by an amount proportional to the driving frequency ω (i.e. fundamental and harmonic overtones); (2) the peak amplitude of the fundamental frequency shift is proportionall to 1/ω in accordance with the theory. The advantage of using a sinusoidal applied field instead of a pulsed square-wave is discussed.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call