Laser ionization and spectroscopy of Cu in superfluid helium nanodroplets

Mass and optical spectroscopic methods are used for the analysis of copper (Cu) atoms and clusters doped to helium nanodroplets (He_N). A two-color resonant two-photon ionization scheme is applied to study the Cu ²P[Formula: see text]S_1/2 ground state transition. The absorption is strongly broadened for Cu atoms submerged inside helium nanodroplets and a comparison with computed literature values is provided. An observed ejection of the dopant from the droplet is triggered upon excitation, populating energetically lower states. The formation of Cu clusters up to Cu₇ inside helium nanodroplets was observed by means of electron impact ionization mass spectroscopy.