Ultrafast electron-nuclear wavepacket in O2+ generated and probed with attosecond pulse trains

We observed the dynamical evolution of the electron-nuclear wavepacket composed of the B-2 Sigma(-)(g) and 3(2)Pi(u) states of O-2(+) with an evolution period of 1.3 fs. We created a dissociative wavepacket of O-2(+) by photoionization of O-2 with the irradiation of an intense attosecond pulse train (APT) in the extreme ultraviolet (XUV) wavelength region, and probed it with another XUV APT by scanning delay between the two APTs. We revealed the evolution of the electron-nuclear wavepacket by the analysis of the spectral phase in the Fourier transform of the recorded delay dependent momentum spectrum of O+. We also found the correlation between the photon energy and the released kinetic energy originating from the dissociation of Rydberg states of O-2 followed by the autoionization of the fragment O atom in the Rydberg states.