The relative intensities of 16 of the more important multiplets of normal titanium have been measured in the vacuum arc. The intensities of the multiplets in triads are found to agree with Kronig’s intensity formulas. The agreement is closest if the effective temperature of the arc is taken as 10,0000°A. when the average deviation is about 7%. This is shown to be as good as could be expected, considering the wide separations involved, and the uncertainty of the ν4 and excitation corrections, together with the fact that some of the multiplets contain lines which are abnormal in intensity. A triad due to a two-electron transition is shown to agree with Kronig’s formulas for the most closely analogous one-electron transition. Certain definite deviations from the intensity formulas which cannot be due to experimental error are noted. The strongest line in the spectrum under normal excitation conditions is found to be λ3653.49, confirming the selection of this as the raie ultime by spectrochemical means. A number of quintet system lines were found to be stronger fundamentally than this, however, the greater inner quantum numbers overcoming the disadvantage of elevation of the metastable state. Curves showing the relative amounts of self-reversal in multiplets coming from different lower states in the atom are given.
GEORGE R. HARRISON and HARRY ENGWICHT, "INTENSITY RELATIONS IN THE SPECTRA OF TITANIUM II. RELATIVE INTENSITIES OF THE STRONGER MULTIPLETS OF TI I," J. Opt. Soc. Am. 18, 287-300 (1929)