The spectrum of triply ionized tungsten (W IV) was produced in a sliding-spark discharge and recorded photographically on the NBS 10.7 m normal-incidence vacuum spectrograph in the 600-2600 A spectral region. The analysis has established all 37 levels of the 5 d 3 , 5d2 6s and 5d6s2 even configurations and all 68 levels of the 5d26p and 5d6s6p odd confugurations. A total of 774 lines have been classified as transitions between these levels. Comparison of observed level values with those calculated in a least-squares fit shows an rms deviation of f 50 cm-' for the even configurations and c 250 cm-' for the odd ones.

The spectrum of Mo V was observed in the wavelength region from 250 to 6000 Å, using a variety of spectrographs and light sources. The level system was revised and extended to include all but one of the levels of 4d2, 4d5s, 4d5d, 4d6s, 4d5p, 4d6p, 4d4f and 5s5p. Hartree-Fock calculations were made and also parametric least-squares calculations including configuration interaction. Scaling factors between Hartree-Fock and least-squares values for the interaction integrals were obtained and used for an isoelectronic comparison. The ionization potential was estimated to be 54.49 ± 0.02 eV.

The spectrum of doubly ionized tungsten (W III) was produced in a sliding-spark discharge and recorded photographically on the NIST 10.7-m normal-incidence vacuum spectrograph in the 600–2680 Å spectral region. The analysis has led to the establishment of 71 levels of the interacting 5d4, 5d3 6s and 5d2 6s2 even configurations and 164 levels of the interacting 5d3 6p and 5d2 6s 6p odd ones. A total of 2636 lines have been classified as transitions between the 235 experimentally determined levels. Comparison between the observed levels and those calculated from matrix diagonalizations with least-squares fitted parameters shows an rms deviation of ±87 cm−1 for the even configurations and ±450 cm−1 for the odd ones.

No abstract

The spark specLruffi of gold has b een photog raph ed in a helium atmosphere f ro m 500 A to 6600 A. Abo u t 500 lines have been assigned to t he third sp ectrum, Au III, a nd separated f rom t hose belonging to diffe rent stages of ioni zation, by observation of the polarity of the lines. Sixty two le vels ha ve been found: 17 evcn levels, a ri sin g from t he 5d9 a nd 5dB 68 con fi gurations; ancl45 odd levels, belonging to the 5dB 6p a nd 5d7 68 6p configurations. All of the expected lcvels from the confi gurations 5d9, 5dB 68 a nd 5d8 6p have been iden tified excep t for the very hi gh terms based on the 5dB(IS) core of Au IV. ' Wi t h Lh ese le vels it was possible to elas~ify 256 lin es.