Abstract
The refractive indices and absorption edges of liquid bromine and iodine have been measured over the temperature ranges 19 to 57°C and 114 to 181°C respectively, and at wavelengths from the absorption edge (700 nm in bromine and 1100 nm in iodine) up to 1800 nm. At 1800 nm the indices are 1.604 in bromine at 19°C, and 1·934 in iodine at 114°C; both liquids are strongly dispersive. The temperature dependence of the refractive index appears to result largely from the thermal expansion of the liquids, and is fairly well accounted for by the Lorenz-Lorentz equation. The absorption edges in both liquids show well-defined exponential regions; neither the positions nor the slopes of the edges depend strongly on temperature. The optical properties of liquid bromine show little evidence of molecular interactions; in liquid iodine they are significant but not dominant. The experimental data on molecular electronic polarizabilities are in good agreement with calculated values.