Quasielastic light scattering from nematicp-methoxybenzylidene-p′−n-butylaniline (MBBA)

The quasielastic scattering of laser light from nematic MBBA is studied utilizing homodyne procedures. The results stem from a comprehensive study of the half widths and areas of the "slow mode" peaks together with their temperature and angle dependence. The data taken at small angles yield the temperature-dependent ratios of the viscosity coefficients to curvature elastic constants for twist, bend, and splay. From these ratios, utilizing data of others, the temperature dependence of the twist elastic constant $K_{22}$, and twist, splay, and bend viscosity coefficients ${\gamma }_1$, ${\eta }_s$, and ${\eta }_b$, respectively, are determined. From the data taken at large angles the values of ${\alpha }_4^{\prime }$ and ${\alpha }_v^{\prime }$ (which is found to be negative) are determined at a reduced temperature, $T_R=0.96\mathrm{}$.