Revised absolute absorption cross sections of CaI at 1886.5 and 1765.1 AA

Abstract

The photo-ionization cross sections of CaI are measured photo-electrically at 1886.5 and 1765.1 AA; hooks of the 4226.78 AA resonance line are used to establish number densities. The resulting values for the absorption cross sections of 52 and 71*10-18 cm2 respectively are larger by a factor of 2.2 than previously published values based on vapour pressures.