Concept of mismatch and relaxation explains DC and AC conductivities of fragile glass-forming ionic melts

In fragile glass-forming ionic melts, spectra of the ionic conductivity have been taken in wide ranges of frequency and temperature. In our experiments, we have studied 0.4Ca(NO3)(2).0.6KNO(3) and LiCl . 7H(2)O over more than ten decades on the frequency scale, including the far infrared. The results exhibit characteristic traits, and a clear-cut picture is found to emerge from them. We present a phenomenological description of our data as well as a set of equations which fit them surprisingly well. Those equations are then traced back to their dynamic origins on atomic scales of length and time. The underlying dynamic principle which is thus revealed is called the concept of mismatch and relaxation (CMR). (C) 2001 The Electrochemical Society.