Refractive indices of water and ice in the 065- to 25-μm spectral range

New accurate values of the imaginary part, k, of the refractive index of water at T = 22 °C, supercooled water at T = -8 °C and polycrystalline ice at T = -25 °C are reported. The k spectrum for water in the spectral region 0.65-2.5 µm is found to be in excellent agreement with those of previous studies. The k values for polycrystalline ice in the 1.44-2.50-µm region eliminate the large uncertainties existing among previously published conflicting sets of data. The imaginary part of refractive index of supercooled water shows a systematic shift of absorption peaks toward the longer wavelengths compared with that of water at warmer temperatures.