Dynamical properties of small and large 2-D Coulomb clusters in complex plasmas

Normal mode spectra of finite two-dimensional dust clusters of microspheres in a complex plasma have been measured and analyzed. The mode spectra have been obtained from the thermal Brownian motion of the microspheres. Here, small, medium, and large clusters have been investigated in view of the transition from the normal mode spectrum of finite clusters to the dispersion of waves in infinite systems.