Dielectric relaxation mechanism in liquid crystals

The relaxation mechanism and the strength of interaction in MBBA, EBBA, PAA and cholesteric liquid crystals have been theoretically studied using the density matrix approach to determine the physical basis. The exponent of the angular frequency (n) transforms the time independent transition rate to a time dependent transition rate and its value is around 0.54±0.05. The ratio of the change in two time scales is related to a decrease in entropy and to the ordering of the molecular arrangement in the liquid crystals. The density matrix approach better explains the long time relaxation phenomenon and the singularity at n=0. This approach also gives a quantitative definition of the key parameter n. The time scale transformation under the density matrix approach is such that the causality principle of a Gaussian orthogonality ensemble random Hamiltonian is satisfied. An additional advantage is the use of 1-trick for cumulative perturbation to any desired long time relaxation. We found that there is no systematic variation of the key parameter versus temperature