The smectic potential in a liquid crystal with a reentrant nematic phase: NMR of solutes

Separation of nematic and smectic-A potential effects on solute ordering in a series of binary 6OCB–8OCB mixtures

“…We have extended the study of molecular ordering to the smectic phase where nematic ordering remains but a new smectic or-der parameter is born. [6][7][8][9][10] Here we have uncovered unusual behaviourwhile linear extrapolation of the nematic ordering potential into the smectic phase works well for some solutes, it does not for others. In this paper we study a LC system with a Nsmectic A -(re-entrant) N phase sequence 8 where the smectic range is variable, allowing us to investigate this unusual behaviour quantitatively.…”

NMR of solutes in nematic and smectic A liquid crystals: the anisotropic intermolecular potential

“…The experimental S i i are used for the exact fitting of the solute orientational order parameters to the two independent β i i energy parameters b and β x x (skeletal points). The intercepts and slopes of the straight lines drawn through the nematic skeletal points for mdcb and pdcb are reported by Yethiraj et al ., while odcb has a curved fit to the nematic points as detailed in Yethiraj et al . The open circles are the b and values from the fit to the smectic potential, Eqn .…”

“…In this case, a curve that goes through both N and RN points is used in order to extrapolate the N potential into the SmA phase. For mdcb, but not for pdcb, the linear extrapolation of the N points goes through the RN points …”

“…The points for the nematic phase are to the left, and those for the smectic A phase to the right, with the two filled points to the far right being from the RN phase. Reproduced with permission from parts of Figures 1 and 2 of Yethiraj et al …”

Recent NMR Studies of Thermotropic Liquid Crystals

“…For 1,2-dichlorobenzene (odcb) as an example, β odcb,zz (1) and β odcb,zz (2) are equal to À 0.927 and À 0.285, respectively, while β odcb,yy (1) and β odcb,yy (2) are 0.333 and 0.156, respectively in the two MS mechanisms. Given the assumptions made in previous studies using KM theory [345][346][347] and the success of the MSMS potential in dealing with nematics, the Hamiltonian for the potential in a smectic liquid crystal is taken as:…”