The A and Am-Fm stars. I. The abondances of Li, Al, SI and Fe.

Twenty five A and Am stars, mostly field stars, (and five reference late-F stars) have been observed for their Li content with the European Southern Observatory coude auxiliary telescope and the Canada-France-Hawaii telescope at high spectral resolution and high signal-to-noise ratios. Photospheric abundances have been determined for Li, Al, Si, and Fe from a model atmosphere abundance analysis with the most homogeneous processing. The characteristic of Am-Fm stars with respect the normal stars to be Ca underabundant is investigated thanks to results of the refined spectral classification for the B8-F2 stars by Gray R. O. and Garrison R. F. (1987, ApJS, 65; 1989, ApJS, 69 and 70)