Revised analysis of the fifth spectrum of rhenium (Re V)

The spectrum of rhenium was observed in the (500-2100) Å wavelength region. A 6.65 m normal incidence VUV spectrograph has been used to record the spectrum. The (5d3+5d26s)-5d26p transition array of four times ionized rhenium, Re V, has been investigated. The configurations 5d3, 5d26s and 5d26p had been previously studied, and all but one levels of these configurations (19, 15 and 45 levels, respectively) had been established. The previous analysis was based on 382 classified spectral lines. In the current analysis we have rejected 74 previously identified spectral lines and added 90 newly classified lines. New list of identified lines contains 398 entries. Comparing with the previous analysis, the current study is based on new spectrograms and significantly more accurate wavelength measurements. We have detected a large (up to 35 mÅ) systematic shift in wavelength measurements used in the previous analysis. In the current study, the standard deviations (by regions) of the undisturbed isolated lines from their Ritz positions are three to five times smaller and the largest deviation of strong isolated lines from their Ritz positions is about seven times smaller than in the previous work. We have confirmed identification of all but three previously found levels. One level has been rejected and two levels have been determined at new positions. One previously unidentified 5d26s level has been added. Based on the new wavelength measurements, we have corrected positions of all previously known 5d3, 5d26s and 5d26p energy levels (except for the ground level, rejected and newly determined levels) by up to 8.31cm−1. From all 80 theoretically possible levels of the configurations 5d3, 5d26s and 5d26p, only the level 5d26s (1S)2S1/2 is still not determined. The orthogonal operators technique was used to calculate the level structure and transition probabilities. The energy parameters have been determined by the least squares fit to the observed levels. Calculated transition probabilities, energy values, as well as LS-compositions obtained from the fitted parameters are presented.