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Published wavelengths aiJd estimated intensities of lines characteril'ling the first two spectra of columbium (RP881) have been supplemented by observations of the arc spectrum (6500 to 8500 A) in an atmosphere of helium, by observations of the spark spectrum (2000 to 2100 A), and by measurements of the Zeeman patterns for 1,557 lines. All available data have been analyzed for the purpose of correcting and extending the information about the structures of Cb II and Cb I (RP793).The Cb II The Cb I table contains 3,313 lines (2164.54 to 10920.7 A), 2,836 of which have been interpreted as combinations of 364 atomic energy levels representing 58 doublet, 55 quartet, and 13 sextet spectral terms. The lowest term (normal state of neutral Cb 'atoms is (4d l 58):a 6Do~, and the strongest line of the Cb I spectrum is the transition (4d' 5s) a6D,~-(4d' 5p) y 6F5~' with a wavelength of 4058.931 A.The Cb I spectrum is largely accounted for by transitions between levels arising from 4d' 5s or 4d 3 5s 2 and 4d' 5p or 4d 3 585p electron configurations.Zeeman patterns measured for 911 Cb I lines have been 90 percent interpreted in this analysis, which now includes 86 percent of the known lines and over 93 percent of their intensity. Two members of the series (4d 4 ns) 6D and two each of (4d 3 58 np) 4(DFG) have been established. Extrapolation of these indicates a limit of 54,600 cm-I , which represents the energy difference between the normal states of Cb atoms and Cb+ ions. The corresponding ionization potential for neutral columbium atoms is 6.77 volts.

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The infrared absorption spectrum of carbon disulfide has been remeasured in the region from 2 to 24 I' with cells up to 5 mm in t hickness. Fifteen bands were observed , some howe ver being of low in tensity. The strongest band for the liquid occurs at 6.621' , and t he second harmonic of this band was observed at 2.22 1', but t he first harm onic, which should be at about 3.33 1', was not observed, in accordance with the selection rules for a symmetrical linear molecule. Four combination bands were observed between 3 and 5 1' , whose wavelengths " 'ere in good agreement with the calculated values. A combination band , which is represented by the difference between t wo fundam entals, occurs a s a broad, moderately st.rong band in t he region of 11.61'. A weak band, observed at 15.271-'< corresponds with the wavelength of t he inactive vibration of the molecule. Howe ver, when t his region was t udied with a 140 cm cell filled with the saturated vapor of C82 at room temperature, no baml was observed . In the vapor state a total of six bands were found at wavele,1gths less than 201' . The fund amental band at 6.5 I' shows a side branch that is probably due to t he isotopi c effect produced by C13. 80me small bands t hat were observed may be attribu ted to the 02832834 molecule. As would be expected for t his molecular configuration , the spectrum of C82 as observed may b e classified into an array of terms analogou s to those of CO2• A band at 12.7 I' has d ifferent intensities for samples obtained from two differen t sources and may be caused by an impurity. This band did not appear when the cell containing t he vapor was used.

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