XXXVI Reunión Bienal de la Real Sociedad Española de Física

Structure and dynamics of ions in gas phase: interplay between experiments and theory in IRMPD spectroscopy

18 jul. 2017 15:45

20m

Aula Matemáticas (Facultad de Química (USC))

Oral parallel contribution Molecular Physics at the Edge Molecular Physics at the Edge I

Descripción

IR vibrational spectroscopy is a widespread technique for the characterization of molecules in gas phase, highly sensitive to small structural changes, like hydrogen bonding patterns, thus allowing the detection of motifs and signatures o¬¬ccurring in relevant processes. In the case of gaseous ions, the low density of the sampled species requires the use of a sensitive 'action' spectroscopy approach such as IRMPD (IR Multiple Photon Dissociation) spectroscopy. By this technique the fragmentation due to absorption of multiple IR photons in resonance with active vibrational modes of the molecular ion is probed by mass spectrometry. The IRMPD spectrum is then obtained by reporting photo-fragmentation yield as a function of the IR photon energy. The interpretation of the experimental spectra needs in any case a strong computational support to correctly assign the main features to the corresponding vibrational modes and to identify the populated isomers and/or conformers, particularly when flexible molecule are investigated. This combined approach has recently allowed a comprehensive description at the molecular level for the reactive events responsible for cisplatin activity, including the first direct evidence of a prototypical Eigen-Wilkins encounter complex in solution. The last years have also witnessed increasing applications of IRMPD kinetics experiments, where the use of selected active IR photons can produce selective photo-fragmentation of different isomers or even different conformers, thus enabling the qualitative and quantitative characterization of their population in the experimental mixture.