Visualizing recurrently migrating hydrogen by few-cycle intense laser pulses

Ultrafast hydrogen migration in deuterated acetylene dication (C2D22+) is studied by the pump-probe Coulomb explosion imaging with few-cycle intense laser pulses (9 fs, 0.13 PW/cm2, 800 nm). The temporal evolution of the momenta of the fragment ions produced by the three-body explosion, C2D23+ → D++ C+ + CD+, shows that the migration proceeds in a recurrent manner: The deuterium atom first shifts from one carbon site to the other in a short time scale (∼90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation