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Investigation of XUV-induced ultrafast electron dynamics in complex molecules

I-23

Investigation of XUV-induced ultrafast electron dynamics in complex molecules


F. Calegari1, D. Ayuso2, A. Trabattoni3, S. Anumula3, L. Belshaw4, S. De Camillis4, F. Frassetto5, L. Poletto5, A. Palacios2, P. Decleva6, J. Greenwood4, F. Martín2, M. Nisoli1,3

1IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy

2Universidad Autónoma de Madrid. 28049 Madrid, Spain

3Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy

4Centre for Plasma Physics, Queen’s University Belfast, BT7 1NN, UK

5IFN-CNR, Via Trasea, 7 - 35131 Padova, Italy

6Università di Trieste, 34127, CNR-IOM, Trieste, Italy

Electron transfer within a single molecule is the fundamental step of many biological processes and chemical reactions. Theoretical studies have pointed out that very efficient charge dynamics along the molecular backbone can be driven by purely electronic effects, which can evolve on a temporal scale ranging from few femtoseconds down to tens of attoseconds [1]. Here, we report the application of XUV (17-35 eV) attosecond pulses to prompt ionization of the amino acid phenylalanine and the subsequent detection of ultrafast dynamics on a sub–4.5-femtosecond temporal scale (Fig. 1), which is shorter than the vibrational response of the molecule [2]. This ultrafast dynamics can only be associated with a purely electronic process, thus constituting the first experimental measurement of charge migration in a biomolecule.

Figure: (a) Oscillatory pattern observed in the measured dication yield (m/q=60) as a function of the XUV pump- IR probe delay. (b) Calculated variation of the hole-density as a function of time.

Figure: (a) Oscillatory pattern observed in the measured dication yield (m/q=60) as a function of the XUV pump- IR probe delay. (b) Calculated variation of the hole-density as a function of time.

References:

[1] L. S. Cederbaum et al., Chem. Phys. Lett. 307, 205 (1999)

[2] F. Calegari et al, Science 346, 336-339 (2014)