title: Strong-field-induced wave packet dynamics in carbon dioxide molecule.
abstract: Temporal evolution of electronic and nuclear wave packets created in strong-field excitation of the carbon dioxide molecule is studied employing momentum-resolved ion spectroscopy and channel-selective Fourier analysis. Combining the data obtained with two different pump-probe set-ups, we observed signatures of vibrational dynamics in both, ionic and neutral states of the molecule. We consider far-off-resonance two-photon Raman scattering to be the most likely mechanism of vibrational excitation in the electronic ground state of the neutral CO2. Using the measured phase relation between the time-dependent yields of different fragmentation channels, which is consistent with the proposed mechanism, we suggest an intuitive picture of the underlying vibrational dynamics. For ionic states, we found signatures of both, electronic and vibrational excitations, which involve the ground and the first excited electronic states, depending on the particular final state of the fragmentation. While our results for ionic states are consistent with the recent observations by Erattupuzha et al. [J. Chem. Phys.144, 024306 (2016)], the neutral state contribution was not observed there, which we attribute to a larger bandwidth of the 8 fs pulses we used for this experiment. In a complementary measurement employing longer, 35 fs pulses in a 30 ps delay range, we study the influence of rotational excitation on our observables, and demonstrate how the coherent electronic wave packet created in the ground electronic state of the ion completely decays within 10 ps due to the coupling to rotational motion.
authors.affiliation: J.R Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA. rudenko@phys.ksu.edu and Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: Artem
authors.initials: A
authors.lastname: Rudenko
authors.affiliation: J.R Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA. rudenko@phys.ksu.edu and Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
authors.forename: Varun
authors.initials: V
authors.lastname: Makhija
authors.affiliation: J.R Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA. rudenko@phys.ksu.edu and Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: Aram
authors.initials: A
authors.lastname: Vajdi
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Ergler
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schürholz
authors.affiliation: J.R Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA. rudenko@phys.ksu.edu.
authors.forename: Rajesh K
authors.initials: RK
authors.lastname: Kushawaha
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany and Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Ullrich
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Moshammer
authors.affiliation: J.R Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA. rudenko@phys.ksu.edu.
authors.forename: Vinod
authors.initials: V
authors.lastname: Kumarappan