Effect of Temperature on the Vacuum Ultraviolet Transmittance of Lithium Fluoride, Calcium Fluoride, Barium Fluoride, and Sapphire*

Abstract

The effect of temperature on the vacuum ultraviolet transmittance of LiF, CaF2, BaF2, and sapphire has been measured. At the short-wavelength edge, the transmittance curves shift to longer wavelengths as the temperature is raised. Thus, near the short-wave cutoff, windows are rendered opaque to the shortest wavelengths by relatively modest increases in temperature. The importance of these observations to vacuum ultraviolet photochemistry and spectroscopy at elevated temperatures is discussed.