Comprehensive optical and collision data for radiation action. II. Ar

We present a complete set of optical oscillator strengths and electron impact cross sections for argon gas. The cross sections were obtained utilizing a semiempirical method of Platzman which stresses the close relationship between photoabsorption and fast electron−atom collisions. The data evaluation was done by analyzing a great variety of experimental measurements of various nature and piecing them together on the basis of theory, with the constraints of sum rules. The mean energy per ion pair, W, calculated from adopted cross sections allowing for inner shell contributions is 26.9 eV. This value is expected to exceed the measured value of 26.4 eV, which is reduced by the contribution of collateral ionization.