Photospheric abundances are presented for 27 elements from carbon to europium in 181 F-G dwarfs from a differential LTE analysis of high-resolution and high signal-to-noise spectra .
Stellar effective temperatures ( T _ { eff } ) were adopted from an infrared flux method calibration of Strömgren photometry .
Stellar surface gravities ( g ) were calculated from Hipparcos parallaxes and stellar evolutionary tracks .
Adopted T _ { eff } and g values are in good agreement with spectroscopic estimates .
Stellar ages were determined from evolutionary tracks .
Stellar space motions ( U,V,W ) and a Galactic potential were used to estimate Galactic orbital parameters .
These show that the vast majority of the stars belong to the Galactic thin disc .

Relative abundances expressed as [ X/Fe ] generally confirm previously published results .
We give results for C , N , O , Na , Mg , Al , Si , S , K , Ca , Sc , Ti , V , Cr , Mn , Co , Ni , Cu , Zn , Sr , Y , Zr , Ba , Ce , Nd , and Eu .
The \alpha -elements – O , Mg , Si , Ca , and Ti – show [ \alpha /Fe ] to increase slightly with decreasing [ Fe/H ] .
Heavy elements with dominant contributions at solar metallicity from the s -process show [ s /Fe ] to decrease slightly with decreasing [ Fe/H ] .
Scatter in [ X/Fe ] at a fixed [ Fe/H ] is entirely attributable to the small measurement errors , after excluding the few thick disc stars and the s -process enriched CH subgiants .
Tight limits are set on ‘ cosmic ’ scatter .
If a weak trend with [ Fe/H ] is taken into account , the composition of a thin disc star expressed as [ X/Fe ] is independent of the star ’ s age and birthplace for elements contributed in different proportions by massive stars ( Type II SN ) , exploding white dwarfs ( Type Ia SN ) , and asymptotic red giant branch stars .

By combining our sample with various published studies , comparisons between thin and thick disc stars are made .
In this composite sample , thick disc stars are primarily identified by their V _ { LSR } in the range -40 to -100 km s ^ { -1 } .
These are very old stars with origins in the inner Galaxy and metallicities [ Fe/H ] \leq - 0.4 .
At the same [ Fe/H ] , the sampled thin disc stars have V _ { LSR } \sim 0 km s ^ { -1 } , and are generally younger with a birthplace at about the Sun ’ s Galactocentric distance .
In the range - 0.35 \geq [ Fe/H ] \geq - 0.70 , well represented by present thin and thick disc samples , [ X/Fe ] of the thick disc stars is greater than that of thin disc stars for Mg , Al , Si , Ca , Ti , and Eu .
[ X/Fe ] is very similar for the thin and thick disc for – notably – Na , and iron-group elements .
Barium ( [ Ba/Fe ] ) may be underabundant in thick relative to thin disc stars .
These results extend previous ideas about composition differences between the thin and thick disc .