Nuclear quadrupole proton magnetic cross relaxation spectra analysis in a smectic A mesophase

ESTEBAN ANOARDO; DANIEL PUSIOL

JOURNAL OF MOLECULAR STRUCTURE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2000

0022-2860

In a previous paper, we reported an experimental study of 35Cl quadrupole dips in the proton spin?lattice relaxation dispersion (T (n)) of a chlorinated liquid crystal specially synthesized for this work (4ClOB). In contrast with existing literature, our dip shapes were not symmetric. We could successfully fit the experimental data with a model previously used to fit nuclear quadrupole resonance line shapes in solids, based on the existence of a distortion field function (DFF), describing the local order properties of the condensed phase. However, the model allowed us to fit data without defining explicitly such DFF, while theobtained numerical coefficients lacked physical meaning. In the present work, the model is applied to a liquid crystal by defining an orientational DFF for coefficient evaluation. The analysis allowed us to obtain important information about the studied molecule structure and its dynamics in the mesophase. Results are in good agreement with the semiempirical quantum simulations of free molecule structure.1