Self-consistency of Vuks equations for liquid-crystal refractive indices

Vuks equations correlate the microscopic molecular polarizabilities to the macroscopic refractive indices of anisotropic crystalline materials. For anisotropic liquid crystals, the molecular polarizabilities are difficult to measure directly due to the short- and long-range interactions. We have converted Vuks equations into different forms. By measuring the refractive indices at different temperatures and wavelengths, the Vuks equations can be validated. Five liquid-crystal materials with refractive index ranging from ∼1.46 to ∼1.86 are used to validate the modified Vuks equations. The experimental results agree with the theory very well. Based on the Vuks equations, the molecular polarizabilities of 4-cyano-4-n-pentylbiphenyl are calculated.