Revisiting the relaxation dynamics of isolated pyrrole

• Published in: The Journal of chemical physics 2014-07, Vol.141 (1), p.014303-014303
• Main Authors: Montero, Raúl, Ovejas, Virginia, Fernández-Fernández, Marta, Peralta Conde, Álvaro, Longarte, Asier
• Format: Article
• Language: English
• Subjects: ATOMIC AND MOLECULAR PHYSICS; EXCITATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IONS; PHOTOELECTRON SPECTROSCOPY; PROBES; PYRROLES; RELAXATION; RESONANCE; WAVELENGTHS
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.4885722

Herein, the interpretation of the femtosecond-scale temporal evolution of the pyrrole ion signal, after excitation in the 267-217 nm interval, recently published by our group [R. Montero, A. Peralta Conde, V. Ovejas, M. Fernández-Fernández, F. Castaño, J. R. Vázquez de Aldana, and A. Longarte, J. Chem. Phys. 137, 064317 (2012)] is re-visited. The observation of a shift in the pyrrole(+) transient respect to zero delay reference, initially attributed to ultrafast dynamics on the πσ* type state (3s a1 ← π 1a2), is demonstrated to be caused by the existence of pump + probe populated states, along the ionization process. The influence of these resonances in pump-prone ionization experiments, when multi-photon probes are used, and the significance of a proper zero-time reference, is discussed. The possibility of preparing the πσ* state by direct excitation is investigated by collecting 1 + 1 photoelectron spectra, at excitation wavelengths ranging from 255 to 219 nm. No conclusive evidences of ionization through this state are found.