Tagging multiphoton ionization events by two-dimensional photoelectron spectroscopy.

Two-dimensional photoelectron spectroscopy has been used to supply process-specific labels to multiphoton ionization events. Employing these tags, the authors can construct excitation and photoelectron spectra along predefined excitation routes in the neutral manifold and ionization routes to the ionic manifold from one single two-dimensional photoelectron spectrum. These results offer a novel way to elucidate the vibronic and dynamic properties of excited and ionic states.