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High-frequency asymptotic shape of the primary relaxation in supercooled liquids

Figures 1 (a) to (d) show ε " (ν ) for the four liquids at several tem peratures. Our measure­ m ents span from 10~3 Hz to 107 Hz. Rather than extend our range to higher frequency to determ ine the shape ε " {ν ) above i/p, we have measured the response at the lowest possible tem peratures, thus positioning the peak at very low frequency. This strategy has three ad­ vantages: 1) it allows us to characterize the relaxation as close as possible to the proposed low-tem perature transition; 2) it avoids overlap in the spectrum with any microscopic peaks or other features at high frequency [3], [11]; and 3) it enables us to measure ε" (ν ) through the entire frequency range with one capacitor geometry, thus avoiding the introduction of scaling factors to connect different regions of the spectra, as is typically necessary with higherfrequency m easurements.