Remarks on the Proton NMR of Di-Heptyloxyazoxybenzene in the Smectic-C Phase

It is suggested that the ideal smectic-C reorientation model be modified to include both some rotational slipping of the smectic-C domains and hindered reorientation of a small percentage of molecules to account for the behaviour of proton NMR in smectic-C di-heptyloxyazoxybenzene. The calculated poly-domain line shapes are rather insensitive to the characteristic biaxial order parameter predicted by molecular models of the smectic-C phase.