NMR in the pseudogap- and charge-density-wave states of (TaSe4)(2)I

We have studied the Se-77 NMR spectrum and spin-lattice relaxation rate (SL RR) in the quasi-one-dimensional conductor (TaSe4)(2)I in the temperature r ange of 150 to 320 K, i.e., both above and below the temperature of the cha rge-density wave transition, T, = 263 K. Both the Knight shift and the SLRR vary strongly with temperature in the entire range investigated with no sh arp feature at T,. In particular, no critical divergence or Hebel-Slichter peak is observed. The SLRR is strongly "non-Korringa", i.e., not proportion al to the square of the Knight shift times temperature. All these findings are interpreted in terms of a fluctuating gap model.