Interferometric determination of the refractive index of liquid sulphur dioxide

The absolute refractive index of liquid sulphur dioxide (SO2) was determine d with an uncertainty of +/-0.0007 with the help of a Michelson interferome ter and a computer-controlled rotatory stage supporting a rectangular fused silica cell, containing the liquid. The measurements were performed at tem peratures around 20 degreesC for the laser line wavelengths 632.8, 514.5 an d 488.0 nm. The experimental data were fitted to the simple Cauchy dispersi on formula. The results calculated from this formula are consistent within the experimental uncertainty with published values obtained at other wavele ngths and/or other temperatures.