Measurement of atomic parameters of singly ionized argon lines—I. Experimental procedure

Abstract

In order to observe spectral lines of ArII, corresponding to transitions from levels of high excitation energy, and to have the highest possible temperature and free electron density in the applied light source, we have observed side-on the near cathode zone of an electric arc of Iarc = 200 A current, burning in pure argon at atmospheric pressure. Spectroscopic diagnostics of the observed zone showed that it was characterized by high temperature and electron densities of the order T ≈ 24,000 K and Ne ≈ 2 × 1023 m−3, respectively. Altogether, we have registered more than 90 spectral lines from different levels and configurations, e.g. for which the upper levels belong to the 4 f configuration (excitation energy Ei > 24 eV), 5 s and 3 d″ (Ei > 22 eV). We were able to determine the transition probabilities of 92 ArII lines, relative to the 480.602 nm ArII line, and Stark widths of some 80 ArII lines. Our transition probabilities and Stark widths for ArII lines, in many cases measured for the first time, are consistent with the best data published up to now and give one of the most complete sets of results. In this first part, we present the applied experimental procedure and characteristics of investigated argon levels. The transition probabilities and Stark widths of ArII lines, measured in our experiments, are presented in the second and third part of this paper, respectively.