Precision measurement of relative oscillator strengths - IX. Measures of Fe I transitions from levels Formula

Abstract

Measurements are presented of the relative oscillator strengths of 52 lines of Fe I, with excitation energies of between 2.18 and 2.49 eV, and with |$\text{log}\,{gf}\,\gt\,-3.23$|⁠, made using the Oxford furnace technique. These measures have a relative accuracy of 0.004 dex (1 per cent). Absolute values are also given with an accuracy of 2.5 per cent, assuming |$\text{log}\,{gf}\,(371.99)\,=\,-0.43\,\pm \,0.01$| (2.3 per cent). Comparisons are made with other experimental data and with the results of theoretical calculations. An expression is proposed for correcting the measured oscillator strengths of Corliss & Warner to give data having an rms deviation from the Oxford values of 0.14 dex, compared with an rms deviation of 0.55 dex for uncorrected data. Measures previously published for six lines are regarded as unsafe, chiefly because of uncertain blending, and these are withdrawn. The previous measurement for λ 381.453 is corrected.