Figure 2.

(a) Ion yield of the immonium dication for Trp (blue dots, shaded error band) and Phe (red dots, shaded error band) as a function of the delay between the XUV attosecond pump pulse and the NIR few-femtosecond probe pulse. The two signals are fitted with a sum of sinusoidal functions (blue and red lines). (b) Inset of the slow envelope of the decaying dynamics in the delay range between 5 and 20 fs.