Fig. 2: Time-resolved photoelectron spectra.
From: Ultrafast relaxation of photoexcited superfluid He nanodroplets
The He nanodroplets contained on average \(\overline{N}=5\ \times \ 1{0}^{5}\) He atoms and were excited to their 1s2s state at the pump photon energy \(h\nu =21.0\) eV (a) and their 1s2p state at \(h\nu =22.2\) eV (b). The probe photon energy is \(h\nu ^{\prime} =4.8\) eV. The horizontal dashed lines indicate the electron energy corresponding to direct two-photon ionization of He. The panels on the right-hand sides show the electron spectra recorded at various fixed pump-probe delays. The bottom panels show the results of fitting the spectra with multiple peaks (area in (c), position in (d)).
