The spectrum of Cr I between 179.8 and 200 nm wavelengths, absorption cross sections, and oscillator strengths

Abstract The absorption spectrum of furnace-heated Cr vapour at wavelengths below 200 nm was recorded photoelectrically and by photography. By use of the hook method, the column density of neutral Cr atoms in the ground state was determined with the aid of the accurately known oscillator strengths of the resonance lines near 427 nm. The absorption cross section of the autoionized lines that dominate the ionization continuum could thus be obtained on an absolute scale. We also measured the wavelengths of many hitherto unreported lines near the ionization limit and derived a new value for the ionization potential, namely 54575.6 ± 0.3 cm-1. Oscillator strengths for some of these lines are also given.