Abstract

The development of attosecond technology in the past few years has enabled the real-time observation of electron motion in atoms, molecules and the condensed matter [1]. As predicted in previous theoretical works [2–6], prompt ionization of large biological molecules may be followed by ultrafast charge migration along the molecular skeleton, preceding any nuclear rearrangement. This ultrafast dynamics, which has been referred to as charge migration [2], has been recently observed in the amino acid phenylalanine [7] in a two-color pump probe experiment, where the fragmentation yields to the charged fragments were measured as a function of the time delay between the two pulses. The Fourier analysis revealed fast beatings associated to the superposition of cationic states resulting from electron ejection from different molecular orbitals. The interaction of the molecule with an ultrashort pulse creates an electronic wave packet containing several ionic states, leading to charge fluctuations along the molecule that may lead to control of the fragmentation paths. In order to fully understand these phenomena and to be able to guide and explain the new generation of time-resolved experiments, a lot of theoretical work is still to be done. Here we will discuss our previous theoretical work in phenylalanine [7] and present our latest results in glycine, where the evaluation of the electronic wave packets generated by an attosecond pulse allowed for the identification of the relevant ionic states involved in the dynamics.

© 2015 IEEE