Suppression of multiple scattering for the critical mixture polystyreneÕ cyclohexane: Application of the one-beam cross correlation technique

Multiple scattering becomes a problem close to the critical point, especially in systems with a large difference in the refractive index and large correlation length amplitudes as for the case of polystyrene/cyclohexane. In this work we demonstrate the application of the one-beam cross correlation technique and show that in the reduced temperature range of t red51.66310 25 – 0.03 the multiple scattering is successfully suppressed. Furthermore, we measured the angular dependent static scattering intensity. By using the amplitude of the cross correlation function we obtained the correct singly scattered intensities. Those corrected intensities can be analyzed in the framework of the Ornstein–Zernike plot to obtain the correlation length j. The analysis of the obtained static data is in good agreement with the dynamic data. Limitations for temperature and angular dependent measurements in the Ornstein–Zernike plot close to Tc are discussed in detail. © 2003 American Institute of Physics. @DOI: 10.1063/1.1574799#