Optical and dielectric functions of liquid glycerol from gas photoionization measurements

Abstract

In the vacuum ultraviolet spectral region, all solids strongly absorb electromagnetic radiation. Thus, optical properties of liquid surfaces must be obtained from reflectance measurements on a sample exposed to near vacuum rather than from a conventional closed-cell arrangement. In the first application of a new reflectance method which measures photon intensities before and after reflection by gas ionization, we have redetermined the optical functions of glycerol. The new data agree generally with those published before in the region of overlap and extend to a higher energy, 24.4 eV. Although the reflectance between 12 and 18 eV is slightly higher than reported previously, the interpretation of dielectric data calculated from the reflectance is unaltered. The plasmon energy now appears to the at 22 eV instead of the value of 20.4 eV measured earlier.