I am having difficulty plotting the following ListPlot. Below I simplified my code. I would like the top x axis to show the corresponding w values that resulted the dots in the plot. For example for the first dot, b=9 and w=1.9. How can I add the w=1.9 value corresponding to this dot on the top x-axis? Thanks
a[b_, w_] := b/(w);
k[b_, w_] := (1 - Exp[-a[b, w]])^2*Exp[-2/w];
ListPlot[{{9, k[9, 1.9]}, {19, k[19, 3]}, {29, k[29, 4]}, {39,
k[39, 5]}}, Frame -> True,
FrameTicks -> {{Automatic, None}, {Automatic, {1.9, 3, 4, 5}}},
FrameLabel -> {{k, None}, {"b", "w"}}]