43rd Conference of The European Group on Atomic Systems (EGAS), Switzerland, 1 - 04 July 2011, pp.168
Laser induced uorescence spectroscopy was applied to investigate the hyperfine structure of atomic niobium transitions in the wavelength range from 560 nm to 620 nm by using a tunable single-mode cw ring laser with two different dyes, Rhodamine 6G and Kiton Red. Free Nb atoms were produced with a hollow cathode discharge lamp cooled with liquid nitrogen running with a current of about 60 mA in an argon atmosphere of 0.8 mbar.
In total, 48 lines have been investigated. The recorded hyperfine patterns of all lines were fitted with Voigt profile using the program FITTER  in order to obtain the magnetic dipole hyperfine constants A of upper and lower levels. For all lines except two, the classification given in  was confirmed. A classification program  was used to classify the new two lines. The suggested transitions were confirmed by the observed fluorescence wavelengths. At the wavelength 581.9415 nm two lines overlap, which could be recorded separately by use of laser induced fluorescence spectroscopy.
The magnetic dipole hyperfine structure constants A determined in this work are compared with reference values from literature, if available ([4,5] and references therein). Results will be presented for 33 levels of odd parity and ve levels of even parity. For eight levels the A constant was determined for the first time.