Room-, liquid-nitrogen-, and liquid-helium-temperature mid-infrared reflectance spectra of lithium fluoride have been measured at near-normal incidence with special emphasis placed on obtaining precise and accurate data in the difficult <i>R</i><sub>minimum</sub> region. The reliability of the measured <i>R</i><sub>min</sub> curves has been evaluated by a previously suggested mathematical technique. Far-infrared data available from the literature were utilized to construct the low-frequency reflection wings. The newly obtained reflectance data have been processed by an improved Kramers-Kronig dispersion-analysis technique, leading to optical indices significantly more reliable than those reported to date.
A. Kachare, M. P. Soriaga, and G. Andermann, "Kramers-Kronig dispersion analysis of LiF reflectance data obtained at ambient and low temperatures," J. Opt. Soc. Am. 64, 1450-1455 (1974)