Wavelengths and hyperfine constants in GaI and GaII derived by Fourier transform spectroscopy

Hyperfine and isotope structure have been studied in 18 Ga II lines, record ed with Fourier transform spectroscopy. For 12 of the lines the observed pa tterns could be analysed, yielding magnetic hyperfine structure constants A for eight Ga II levels. Improved wavelengths are given for a number of pro minent Ga II lines, including centres of gravity and the individual hyperfi ne and isotope components of the lines with significant structure. The components of the spin-forbidden transition 4s(2)4p P-2-4s4p(2) P-4 in Ga I have also been analysed and absolute wavelengths and hyperfine constan ts A are reported.