The Arc Spectrum of Selenium

Abstract

The arc spectrum of selenium, as excited by means of a positive column discharge in helium, has been photographed over the wave-length range 300-11,000A. Four different grating spectrographs were used having dispersions of from 11 to 2.5A per mm. A total of 510 lines has been measured as belonging to the arc spectrum and of these 391 have been classified. Seven series built on the A S state of the ion have been carried to five or more members and the absolute term values are determined to within 0.2 cm" 1 . All the 4£% 4p*(W) 5s, 4£ 3 ( 2 P) 55, and4£ 3 ( 2 £>) 5p terms have been located and also some of the 4=p 3 ( 2 D) Ad terms. Perturbation effects are frequently evident and are illustrated by plots of the various series.

New measurements of the Se I resonance lines

“…The measured wavelengths in the region 1996-1560 A arc given in Table I with their eye-estimated intensities, and for a comparison the previous measurements by Ruedy and Gibbs (1934) are included. The wavelength errors for unaffected lines are estimated not to exceed 0.005/~.…”

“…Calculated wavelengths for 22 of the strongest Sel rcsonance lines are given in Table II (1974) for the 4p4-4p35s transitions, but a considerable discrepancy exists between some of their values and the obscrved emission intensities (Ruedy and Gibbs, 1934). E.g.…”

“…New energy level values are given in Table 111 for those levels wltich are not given by Morillon and Verg6s (1974). Five of these levels had been established already by Ruedy and Gibbs (1934) although three of them have now been given different designations.…”

“…The prcsent measurements were started in order to improve the connection bctwecn the mutually well connected ground configuration levcls (Eriksson, 1972) and the excited levels (Morillon and Verg6s, 1974) and thcreby obtain accurate wavelengths for the resonance lines. Measurements of Se ~ resonance lines have previously been reported in the comprehensive work by Ruedy and Gibbs (1934).…”

Dissociative excitation of selenium atoms in collisions of electrons with Se2 molecules

“…The optical spectrum of selenium atom was first investigated by Ruedy and Gibbs [13] in a wide spectral range of 30-1100 nm. They also suggested the classification for 391 spectral lines out of 510 registered ones.…”