Electron-impact excitation of argon: Optical emission cross sections in the range of 300-2500 nm

We present measurements of optical emission cross sections for excitation from the ground state of the Ar atom into over 185 excited atomic and ionic levels. Measurements were made at electron energies of 25, 50, and 100 eV, at a gas pressure of 5 mTorr. Due to radiation trapping of resonance levels, many of the cross sections depend on the target pressure. Detailed pressure dependence for over 50 levels is also provided. The energy dependence of the excitation cross sections for over 175 levels in the energy range of 0-250 eV are provided as fitted parameters for a standard analytical function. (c) 2007 Elsevier Inc. All rights reserved.