  The analysis of the high-resolution UVES spectra of the CP stars HR 6000 and
46 Aql revealed the presence of an impressive number of unidentified lines, in
particular in the 5000 - 5400 A region. Because numerous 4d-4f transitions of
FeII lie in this spectral range, and because both stars are iron overabundant,
we investigated whether the unidentified lines can be due to FeII. ATLAS12
model atmospheres with parameters [13450K, 4.3] and [12560K, 3.8] were computed
for the individual abundances of HR 6000 and 46 Aql, respectively, in order to
use the stars as spectroscopic sources to identify FeII lines and to determine
FeII gf-values. After having identified several unknown lines in the stellar
spectra as due to (3H)4d - (3H)4f transitions of FeII, we derived stellar log
gf's for them by comparing observed and computed profiles. The energies of the
upper levels were assigned on the basis of both laboratory iron spectra and
predicted energy levels. We fixed 21 new levels of FeII with energies between
122910.9 cm^-1 and 123441.1 cm^-1. They allowed us to add 1700 new lines to the
Fe II line list in the range 810 - 15011 A.
