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 hav e been taken in wide ranges of frequency and temperature. In our experiment s, 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 result s exhibit characteristic traits, and a clear-cut picture is found to emerge from them. We present a phenomenological description of our data as well a s 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 ti me. The underlying dynamic principle which is thus revealed is called the c oncept of mismatch and relaxation (CMR). (C) 2001 The Electrochemical Socie ty.