The conformation and orientational order of 1-ethoxy-4-chlorobenzene dissolved in a nematic liquid crystal

The proton N.M.R. spectrum of a sample of 1-ethoxy-4-chlorobenzene containing a deuteriated methyl group and dissolved in a nematic solvent has been recorded and analysed. The set of dipolar couplings are used to obtain weighted order matrices WSt and (1 - W)Sg for the trans and gauche isomers respectively, where W is the fraction of the trans form; the analysis assumes that only trans and gauche forms are appreciably populated. The magnitude of the individual elements of the order matrices places a limit on W such that it must lie between 0·5 and 0·7. The order matrices St and Sg are compared with the predictions of a mean field theory of orientational order and reasons for the large discrepancies between the two sets of values are discussed.