C-R model for Ar plasmas

We have used a collisional-radiative model to calculate the population densities of the various 3p$^{5}$4s and 3p$^{5}$4p fine-structure levels in both CCP and ICP low temperature Ar discharge plasmas. This model included cross sections for the excitation of various fine-structure levels of Ar calculated with our Relativistic Distorted-Wave approximation. These calculations included distinct Dirac-Fock target wave functions for each fine-structure level and the projectile electron distorted waves were obtained from the continuum Dirac equations. Cross sections for excitation to the 3p$^{5}$4s, 3p$^{5}$4p, 3p$^{5}$3d, 3p$^{5}$5s and 3p$^{5}$5p levels from both the ground state and 3p$^{5}$4s levels were included. We have compared our results with recent OES measurements [1] as well as calculations using cross sections derived from the simple Drawin formula. Our results are in good agreement with the measurements especially for the CCP plasma. \\[4pt] [1] Xi-Ming Zhu and Yi-Kang Pu, J. Phys. D: Appl. Phys. \textbf{43}, 015204 (2010).