Second spectrum of tungsten (W II)

A preliminary report on the second spectrum of tungsten, published in 1938, presented 27 even energy levels and 50 odd energy levels that were derived from 500 W II lines ranging in wavelength from 1961.43 Å to 4348.13 Å. The present paper submits data on 62 even levels, 132 odd levels, and 2,173 classified lines of W II, ranging in wavelength from 1756.6 Å to 6219.77 Å. The ground state of the W + ion is represented by the 6 D 0½ level of a sextet D term arising from the 5 d 4 6 s 1 electron configuration, but the level intervals and magnetic splitting factors indicate considerable departure from LS -coupling, suggesting that coupling intermediate between LS and Jj may be more appropriate for the spectrum W II.