Oblique-incidence absorption spectroscopy studies of the plasmon in potassium halides

Publisher Website
Google Scholar
Abstract
In the three potassium halides KCl, KBr, and KI, longitudinal excitations are precisely studied by the method of oblique-incidence absorption spectroscopy (OIAS) in the vacuum ultraviolet (10–20 eV) utilizing synchrotron radiation as a light source. Transverse absorption spectra of the halides are also observed in this energy region for comparison. A differential transmission ratio (DTR) of linearly polarized radiation is derived from the OIAS studies. In it, a longitudinal absorption appears as a positive peak and a transverse absorption as a negative one. The DTR spectra of these halides clearly show a prominent positive peak which has been ascribed to the plasmon. These results confirm the previous ones also measured by the present author. Several fine features superimposed on the plasmon peak are well resolved. The profiles of the plasmon peaks could be accurately analyzed by using the Lorentz model. The fine structure of the plasmon peak is successfully interpreted in terms of longitudinal-transverse splittings of a large transverse absorption peak and several fine structures on it in these halides.