Observation of Enhanced Excitation of $I_2^{2+}$ by Strong Laser Fields

ORAL

Abstract

Using pump-probe spectroscopy with ultrashort laser pulses, we see an enhancement of the charge-asymmetric dissociation (CAD) channel, $(I_2^{2+})^* \rightarrow I^{2+} + I$, over a narrow range of internuclear separation. The enhancement of the CAD channel appears to come from excitation of the symmetric ground state dissociation channel ($I^{+} + I^{+}$) for two reasons. First, there is a depletion in the symmetric channel at approximately the same pump-probe delay as the asymmetric enhancement. Second, for a fixed delay, the asymmetric channel increases as a function of probe intensity while the symmetric channel decreases. In addition, we find that the kinetic energy of the extra $I ^{2+} + I$ ions decreases for increasing delay. To explain this dependence of the kinetic energy release on delay, we introduce model potential energy curves. Based on these curves, we conclude that the excitation is produced by a resonant 3-photon transition within $I_2^{2+}$ rather than by ionization of $I_2^+$.

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Authors

  • George Gibson

  • Student Workshop

    Physics, Stony Brook University, NY 11794-3800 USA, Physics Department, Western Michigan University, Kalamazoo, MI, 49008, USA, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA, University of Pittsburgh, Pittsburgh, PA 15260, USA, R. Bo\v{s}kovi\'{c} Institute, Zagreb, Croatia, Bose Institute, Kolkata, India, U. Wisconsin, Argonne National Laboratory, U. Kentucky, Kansas State University, Rice University, Oak Ridge National Laboratory, University of Tennessee, Vienna University of Technology, University of Tennessee, Vienna University of Technology, University of North Alabama, Florence, AL, University of Connecticut, LANL, Auburn University, Voronezh State University, Russia, Oak Ridge National Laboratory, Rollins College, ATOMKI, Debrecen, GANIL, Caen, Stony Brook University, NY 11794-3800 USA, Hefei National Lab \& Dept of Chemical physics, Univ of Sci \& Tech of China, Dept of Earth \& Environ Sci, Univ of Illinois at Chicago, EFI \& Dept of Geophys. Sci., UofC, Chem Div, ANL, Phys Div, ANL, Phys Div, Argonne National Lab (ANL) \& Enrico Fermi Institute (EFI), Univ of Chicago (UofC), Department of Physics, University of Turku, 20014 Turku, Finland, Clarendon Laboratory, Oxford, SNL, Univ. Paris Sud, Orsay

  • Student Workshop

    Physics, Stony Brook University, NY 11794-3800 USA, Physics Department, Western Michigan University, Kalamazoo, MI, 49008, USA, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA, University of Pittsburgh, Pittsburgh, PA 15260, USA, R. Bo\v{s}kovi\'{c} Institute, Zagreb, Croatia, Bose Institute, Kolkata, India, U. Wisconsin, Argonne National Laboratory, U. Kentucky, Kansas State University, Rice University, Oak Ridge National Laboratory, University of Tennessee, Vienna University of Technology, University of Tennessee, Vienna University of Technology, University of North Alabama, Florence, AL, University of Connecticut, LANL, Auburn University, Voronezh State University, Russia, Oak Ridge National Laboratory, Rollins College, ATOMKI, Debrecen, GANIL, Caen, Stony Brook University, NY 11794-3800 USA, Hefei National Lab \& Dept of Chemical physics, Univ of Sci \& Tech of China, Dept of Earth \& Environ Sci, Univ of Illinois at Chicago, EFI \& Dept of Geophys. Sci., UofC, Chem Div, ANL, Phys Div, ANL, Phys Div, Argonne National Lab (ANL) \& Enrico Fermi Institute (EFI), Univ of Chicago (UofC), Department of Physics, University of Turku, 20014 Turku, Finland, Clarendon Laboratory, Oxford, SNL, Univ. Paris Sud, Orsay