Anomaly of the nonergodicity parameter and crossover to white noise in the fast relaxation spectrum of a simple glass former -: art. no. 055703

We present quasielastic light scattering and dielectric spectra of the glass former a-picoline. At high temperatures the evolution of the susceptibility minimum is well described by the mode coupling theory (MCT). Below the critical temperature T-c the simple scaling laws of MCT fail due to the appearance of the excess wing of the a process, which shows a universal evolution as a function of log(10) tau(alpha). Taking this into account, however, we observe the predicted cusplike anomaly of the nonergodicity parameter as well as a crossover to "white noise."