EFFICIENT CHARACTERIZATION OF THE ORIENTATIONAL ORDERING OF ESR-ACTIVE PROBES IN SUPERMOLECULAR FLUIDS

Supermolecular fluids often exhibit organized arrangements which order the orientations of solved ESR-active probe molecules. Due to the high microviscosity, the ESR line-shape of the probe virtually reflects the distribution of the resonating frequencies of the involved spin packets and then the degree of orientational order of the probe. An efficient strategy to get precise estimates of both the magnetic parameters of the probe molecule and the width of the spin packet from the ESR spectrum has been developed. This allows us to adjust only the strength of the effective orienting potential in the fit procedure. A study of the orientational ordering of cholestane probe molecule dissolved in side-chain polymeric mesophases provides accurate testing of the procedure.