\begin{table}%t2
  %\centering
\par
   \caption{Range of atmospheric parameters explored by our synthetic spectral library.}
   \label{tab2}
     \begin{tabular}{lll}
  \hline\hline\noalign{\smallskip}
   Temperature (K)              &~3500 $\leq$~~~~$T_{\rm eff}$~~$\leq$ 47~500  
                    &steps of 250 K for $T_{\rm eff} \leq $10~000 K; 
                     proportionally larger for higher $T_{\rm eff}$\\ 
  Gravity (cgs units)   &~~~~0.0 $\leq$~~$\log{g}$~~$\leq$ 5.0  &\\
  Metallicity           &~~$-$2.5 $\leq$ [M/H] $\leq$ +0.5       &\\
  Rotation velocity (km s$^{-1}$)   &~~~~~~~0 $\leq$ ~~{\sl V}$_{\rm rot}$ 
                    ~~$\leq$ 500 & 0, 2, 5, 10, 15, 20, 30, 40, 50, 75, 100 
                    \hfill{for $T_{\rm eff} \leq $ 6000 K}\\
                    &&0, 10, 20, 30, 40, 50, 75, 100, 150, 200, 250, 300, 400, 500 
                     \hfill{for  $T_{\rm eff} > 6000$ K}\\
  Enhancement           & ~~~~~~[$\alpha$/Fe] = 0.0, +0.4             &
                    [$\alpha$/Fe]~=~+0.4 for [M/H]~=~$-$0.5, $-$1.0, $-$1.5\\
  Micro-turbulent velocity (km~s$^{-1}$) &\multicolumn{1}{c}{$\xi$ = 1, 2, 4}
                    & 1 and 4 km s$^{-1}$ for [$\alpha$/Fe]~=~+0.4\\
  ODFs              &\multicolumn{1}{c}{new}&
                    old where new ones not yet available\\
  Predicted lines                   & \multicolumn{1}{c}{excluded} \\
  \hline
  \end{tabular}
   \end{table}