and future precise abundance analysis projects. These new ATLAS models were calculated with a corrected H$_{2}$O linelist. The abundances used for the MARCS models presented in this paper are from @grevesse02, which are nearly identical to @asplund01; the only significant difference is an abundance of scandium 0.12 dex higher than in @asplund01. The range of stellar parameters (T$_{\rm eff}$, log $g$ and \[M/H\]) spanned by the models covers most stellar types found in the Milky Way.

This paper is organized as follows. In Section 2 we describe the parameter range of our ODFs and model atmospheres and give details of the calculation method of ATLAS9 we implemented. Section 3 contains the parameter range and calculation procedure for MARCS models. In Section 4 we compare MARCS and ATLAS9 models with @castelli01, and illustrate how different C and $\alpha$ contents affect the atmosphere. Section 5 contains the conclusions. The grid of ODFs and model atmospheres will be periodically updated in the future and available online[^3].

![The \[C/M\] or \[$\alpha$/M\] content as a function of \[M/H\] of ATLAS9 models (filled circles, Table 1) and MARCS models (open circles, Table 4). Both \[C/M\] and \[$\alpha$/M\] changes independently from each other, and the small steps 