Resonance-enhanced multiphoton ionization spectroscopy of laser-ablated copper atoms

Resonance-enhanced multiphoton ionization (REMPI) spectra of laser-ablated copper atoms entrained in a supersonic free jet expansion are reported. Depending on the ionization scheme employed, and the conditions under which the copper atoms are produced, very different spectra are produced, which are discussed. In some circumstances, high proportions of metastable atoms survive the ablation and expansion process and are clearly seen in the spectra. The spectroscopic transitions for the observed lines are identified, and it is noted that some caution is merited in the assumption that only ground state copper atoms are present following laser ablation.