Results of the classical (top) and differential (bottom) analyses of α Cen A (left) and α Cen B (right). Various analyses are considered (see Sect. 4.2): unconstrained (top panels), constrained assuming excitation balance (middle panels), and constrained assuming ionisation balance (bottom panels). The T_eff and log g values obtained for each line list are shown with a different colour. The vertical and horizontal dashed lines indicate the 1σ range encompassed by the reference T_eff and log g values (Sect. 4.2). The black error bars indicate the weighted mean of all the results (the position along the y-axis in the middle and bottom panels is shifted for clarity). The full results can be found in Tables B.1 and B.2.