  New opacity distribution functions (ODFs) for several metallicities have been
computed. The main improvements upon previous ODFs computed by Kurucz (1990)
are: (1) the replacement of the solar abundances from Anders & Grevesse (1989)
with those from Grevesse & Sauval (1998); (2) the replacement of the TiO lines
provided by Kurucz (1993) with the TiO lines from Schwenke (1998), as
distributed by Kurucz (1999a); (3) the addition of the H2O lines from Partridge
& Schwenke (1997) as distributed by Kurucz (1999b); (4) the addition of the
HI-HI and HI-H+ quasi-molecular absorptions near 1600 A and 1400 A computed
according to Allard et al. (1998). Other minor improvements are related with
some changes in a few atomic and molecular data. New grids of ATLAS9 model
atmospheres for Teff from 3500K to 50000K and logg from 0.0 dex to 5.0 dex have
been computed for several metallicities with the new ODFs. Preliminary
comparisons of the results from the old and new models have shown differences
in the energy distributions of stars cooler than 4500K, in the ultraviolet
energy distribution of metal-poor A-type stars, in the U-B and u-b color
indices for Teff<7000K and in all the color indices for Teff<4250K.
