  First-principles calculations of the conventional and acoustic surface
plasmons (CSPs and ASPs) on the (111) surfaces of Cu, Ag, and Au are presented.
The effect of $s-d$ interband transitions on both types of plasmons is
investigated by comparing results from the local density approximation and an
orbital dependent exchange-correlation (xc) potential that improves the
position and width of the $d$ bands. The plasmon dispersions calculated with
the latter xc-potential agree well with electron energy loss spectroscopy
(EELS) experiments. For both the CSP and ASP, the same trend of Cu$<$Au$<$Ag is
found for the plasmon energies and is attributed to the reduced screening by
interband transitions from Cu, to Au and Ag. This trend for the ASP, however,
contradicts a previous model prediction. While the ASP is seen as a weak
feature in the EELS, it can be clearly identified in the static and dynamic
dielectric band structure.
