Notes. Central wavelengths λ₀, excitation potential of the lower level χ_low, and electronic configurations of the lower and upper levels are taken from Nave et al. (1994). The oscillator strength of the first line has been taken from Bard et al. (1991). The oscillator strength of the second spectral line has been determined from the value of the first one and employing a measured ratio of 2.8 between the gf factors of both lines (priv. comm. from Brian C. Fawcett from the Rutherford Appleton Laboratory). The α and σ parameters are the temperature exponent and cross section values (in units of the square of the Bohr radius ), respectively, needed for the calculation of the line-broadening by collisions with neutral atoms under the ABO theory. In particular, the numbers provided have been obtained by interpolation on the tables provided by Anstee & O’Mara (1995).