Optical Properties of Potassium

Abstract

The dielectric constant of potassium is determined from 2.07 eV to 6.2 eV by using only s -polarized light. The ε 1 -spectrum is expressed by 1.23-(λ/2920) 2 in λ<3600A and 1.14-(λ/2990) 2 in λ>3600A. The ε 1 - and ε 2 -spectra are compared with the other published data, and discussed with the sum rule and the dispersion relation. The loss function is separated from the absorption spectrum for p -polarized light, and is compared with the calculated loss function from the dielectric constant. The two loss functions seem to be different in the half width.