Determination of the 3d34d and 3d35s configurations of Fe V

The analysis of the spectrum of four times ionized iron, Fe V, has led to the determination of the 3d34d and 3d35s configurations. From 975 classified lines in the region 645-1190 A we have established 123 of 168 theoretically possible 3d34d levels and 26 of 38 possible 3d35s levels. The estimated accuracy of values of energy levels of these two configurations is about 0.7 cm-1 and 1.0 cm-1, respectively. The level structure of the system of the 3d4, 3d34s, 3d34d and 3d35s configurations has been theoretically interpreted and the energy parameters have been determined by a least squares fit to the observed levels. A comparison of parameters in Cr III and Fe V ions is given. (orig.)