  UV, visible, and near-infrared spectroscopy is used to study the transitions
of neutral oxygen leading to the emission of broad OI $\lambda$8446,
$\lambda$11287 and $\lambda$1304 in Active Galactic Nuclei. From the strength
of the former two lines, contrary to the general belief, we found that in six
out of seven galaxies, L-beta fluorescence is not the only mechanism
responsible for the formation of these three lines. Because OI $\lambda$13165
is almost reduced to noise level, continuum fluorescence is ruled out as an
additional excitation mechanism, but the presence of OI $\lambda$7774 in one of
the objects suggests that collisional ionization may have an important role in
the formation of OI $\lambda$8446. The usefulness of the OI lines as a reliable
reddening indicator for the broad line region is discussed. The values of
E(B-V) derived from the OI $\lambda 1304/\lambda$8446 ratio agree with those
obtained using other reddening indicators. The observations point toward a
break in the one-to-one photon relation between OI $\lambda$8446 and OI
$\lambda$1304, attributable to several destruction mechanisms that may affect
the latter line.

Astrophysics