and cluster stars have similar ratios of \[Zr/Fe\]. The comparison field star HD 141531 has \[Zr/Fe\] almost identical to the globular clusters.

As in Y03, we estimate the internal errors in the stellar parameters to be [$T_{\rm eff}$]{} $\pm $ 50K, $\log g~\pm$ 0.2, and $\xi_t~\pm$ 0.2. In Table \[tab:parvar\], we show the abundance dependences upon the model parameters.

Discussion {#sec:discussion}
==========

Rubidium
--------

While our mean Rb abundance for NGC 6752 is \[Rb/Fe\] = $-$0.17 $\pm$ 0.06 ($\sigma$ = 0.14), the abundances appear to concentrate around two distinct values. There are two stars with \[Rb/Fe\] $\simeq$ $-$0.02 and three stars with \[Rb/Fe\] $\simeq$ $-$0.25. The two stars with the higher Rb abundances do not have the highest Al abundances and the three stars with the lower Rb abundances are not exclusively the stars with the lowest Al abundances. Given the weakness of the Rb line, the uncertainties in the derived Rb abundances (see Table \[tab:parvar\]), and the small sample size, it is unlikely that the Rb abundances show a dispersion in NGC 6752. Nor do we find evidence for a correlation between \[Al/Fe\] and \[Rb/Fe\], though we recognize that our sample size (5 stars) is much more limited than 