We present a large and updated stellar evolution database for low- , intermediate- and high-mass stars in a wide metallicity range , suitable for studying Galactic and extragalactic simple and composite stellar populations using population synthesis techniques .
The stellar mass range is between \sim 0.5 M _ { \odot } and 10 M _ { \odot } with a fine mass spacing .
The metallicity [ Fe/H ] comprises 10 values ranging from -2.27 to 0.40 , with a scaled solar metal distribution .
The initial He mass fraction ranges from Y=0.245 , for the more metal-poor composition , up to 0.303 for the more metal-rich one , with \Delta Y / \Delta Z \sim 1.4 .
For each adopted chemical composition , the evolutionary models have been computed without ( canonical models ) and with overshooting from the Schwarzschild boundary of the convective cores during the central H-burning phase .
Semiconvection is included in the treatment of core convection during the He-burning phase .

The whole set of evolutionary models can be used to compute isochrones in a wide age range , from \sim 30 Myr to \sim 15 Gyr .
Both evolutionary models and isochrones are available in several observational planes , employing updated set of bolometric corrections and color- T _ { eff } 
relations computed for this project .
The number of points along the models and the resulting isochrones is selected in such a way that interpolation for intermediate metallicities not contained in the grid is straightforward ; a simple quadratic interpolation produces results of sufficient accuracy for population synthesis applications .

We compare our isochrones with results from a series of widely used stellar evolution databases and perform some empirical tests for the reliability of our models .
Since this work is devoted to scaled solar chemical compositions , we focus our attention on the Galactic disk stellar populations , employing multicolor photometry of unevolved field main sequence stars with precise Hipparcos parallaxes , well-studied open clusters and one eclipsing binary system with precise measurements of masses , radii and [ Fe/H ] of both components .
We find that the predicted metallicity dependence of the location of the lower , unevolved main sequence in the Color Magnitude Diagram ( CMD ) appears in satisfactory agreement with empirical data .
When comparing our models with CMDs of selected , well-studied , open clusters , once again we were able to properly match the whole observed evolutionary sequences by assuming cluster distance and reddening estimates in satisfactory agreement with empirical evaluations of these quantities .

In general , models including overshooting during the H-burning phase provide a better match to the observations , at least for ages below \sim 4 Gyr .
At [ Fe/H ] around solar and higher ages ( i.e .
smaller convective cores ) before the onset of radiative cores , the selected efficiency of core overshooting may be too high in our as well as in various other models in the literature .
Since we provide also canonical models , the reader is strongly encouraged to always compare the results from both sets in this critical age range .