Term analyses of the first two spectra of columbium

Abstract

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.

Hyperfine structure investigations of atomic niobium with optogalvanic and laser-induced fluorescence spectroscopy in the near-infrared wavelength range

“…The wavelengths in air were calculated from the wave numbers in vacuum using the dispersion relation (Peck & Reader 1972). The intensities and classifications are given according to Humphreys & Meggers (1945) when a line was listed in this wavelength table. Nineteen lines are new lines, which mean they have not previously been published.…”

“…They are denoted as "nl". Additionally, 16 lines measured in the present work were given in the wavelength tables of Humphreys & Meggers (1945) without classification. They have newly been classified here and are denoted as "nc".…”

“…Using the Ritz combination principle and taking into account the selection rule for electric dipole transitions (∆J = 0, ±1; J = 0 0), the program calculates all possible transitions to and from a chosen energy level. The program does not consider transition probabilities and of course provides much more lines than listed in the wavelength table of Humphreys & Meggers (1945). Therefore, not all transitions calculated by the Ritz combination principle could be found with our experimental conditions.…”

“…Sixty-two of these lines have already been listed in the wavelength tables from Humphreys & Meggers (1945), 14 without classification. The classification for these lines was deduced from the classification program C_ using the hfs patterns as fingerprint.…”

“…E l , J l , E u and J u are the energy and total electronic angular momentum quantum number of the lower and upper level, respectively; intensities Int. according to Humphreys & Meggers (1945), energy levels according to Humphreys & Meggers (1945) and Kröger et al (2004Kröger et al ( , 2007; in the last column the fluorescence wavelength λ f in air is given for the LIFS measurements; nl: new line; nc: new classification; B(Ne): a neon line, B(Nb) blend by a niobium line, B(? ): blend by unclassified line.…”