Laser spectroscopy of LiHe, a van der Waals molecule

ORAL

Abstract

Van der Waals molecules are extremely long-range, extremely weakly-bound molecules [1]. Lithium helium (LiHe) is an interesting van der Waals molecule due to theoretical interest in its molecular structure and properties. We report the first observation of ground state LiHe molecules. We use cryogenic helium buffer gas cooling to produce high densities of atomic lithium at temperatures ranging from 1-5 Kelvin [2]. LiHe molecules are formed by three body recombination: Li $+$ He $+$ He $\leftrightarrow $ LiHe $+$ He (1) The Li density is continuously monitored via laser absorption spectroscopy. LiHe is detected spectroscopically using both laser induced fluorescence and laser absorption spectroscopy. The LiHe spectrum shows good agreement with a theoretical model of the molecular structure, with only a single bound rovibrational state. Our data shows good agreement with the model which describes the expected density of product(LiHe) varies with temperature and reactants' densities [3] and we also use it to determine the binding energy of the LiHe ground state. The measured binding energy is consistent with the calculated value [4]. References [1] B.L Balney and G.E.Ewing, Annual Review of Physical Chemistry 27, 553(1976). [2] Naima Tariq, Nada Al Taisan, Vijay Singh, and Jonathan D.Weinstein.Phys. Rev.Lett.,\textbf{110}, 153201, 2013. [3] N.Brahms, T.V. Tscherbul, P. Zhang, J. Klos, H.R. Sadeghpour, A. Dalgarno, J. M. Doyle, and T.G. Walker, Phys Rev. Lett. \textbf{105}, 033001 (2010). [4] U. Kleinekath\"{o}fer, M. Lewerenz, and M. Mladenovi\'{c} ,Phys.Rev. Lett.,83, 4717-4720, 1999.

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Authors

  • Naima Tariq

    University of Nevada Reno

  • V.V. Shlyaptseva

    California State University, Dominguez Hills, Univ of California - Irvine, University of Chicago, UC Merced, NINT, Dublin Institute of Technology, Ireland, MIT, NASA/GSFC, CRESST/UMBC \& NASA/GSFC, LLNL, MPI for Plasma Physics, Remeis-Sternwarte/ECAP/FAU, Humboldt State University, University of Nevada Reno, The University of Michigan, University of Nevada, Reno, Lawrence Livermore National Laboratory, Sandia National Laboratories, Los Alamos National Laboratory, Laboratory for Laser Energetics, University of Rochester, Univ of Nevada - Reno, University of Nevada, Reno - Physics Department, Jilin University, China, Department of Physics, University of California, Berkeley, Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Advanced Materials Laboratory, National Institute for Materials Science, Department of Physics \& Astronomy, California State University, Long Beach, CA 90840, UC Santa Barbara, Department of Physics and Astronomy, University of California, Riverside, University of California at Merced, Laboratoire de Physique des Plasmas (CNRS/Ecole Polytechnique/UPMC/Universit\'e Paris Sud), Ecole Polytechnique, 91128 Palaiseau, France, University of Nevada, Reno, NV 89557, USA, University of Nevada, Reno, NV 89557 USA, University of Nevada-Reno

  • V.V. Shlyaptseva

    California State University, Dominguez Hills, Univ of California - Irvine, University of Chicago, UC Merced, NINT, Dublin Institute of Technology, Ireland, MIT, NASA/GSFC, CRESST/UMBC \& NASA/GSFC, LLNL, MPI for Plasma Physics, Remeis-Sternwarte/ECAP/FAU, Humboldt State University, University of Nevada Reno, The University of Michigan, University of Nevada, Reno, Lawrence Livermore National Laboratory, Sandia National Laboratories, Los Alamos National Laboratory, Laboratory for Laser Energetics, University of Rochester, Univ of Nevada - Reno, University of Nevada, Reno - Physics Department, Jilin University, China, Department of Physics, University of California, Berkeley, Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Advanced Materials Laboratory, National Institute for Materials Science, Department of Physics \& Astronomy, California State University, Long Beach, CA 90840, UC Santa Barbara, Department of Physics and Astronomy, University of California, Riverside, University of California at Merced, Laboratoire de Physique des Plasmas (CNRS/Ecole Polytechnique/UPMC/Universit\'e Paris Sud), Ecole Polytechnique, 91128 Palaiseau, France, University of Nevada, Reno, NV 89557, USA, University of Nevada, Reno, NV 89557 USA, University of Nevada-Reno

  • V.V. Shlyaptseva

    California State University, Dominguez Hills, Univ of California - Irvine, University of Chicago, UC Merced, NINT, Dublin Institute of Technology, Ireland, MIT, NASA/GSFC, CRESST/UMBC \& NASA/GSFC, LLNL, MPI for Plasma Physics, Remeis-Sternwarte/ECAP/FAU, Humboldt State University, University of Nevada Reno, The University of Michigan, University of Nevada, Reno, Lawrence Livermore National Laboratory, Sandia National Laboratories, Los Alamos National Laboratory, Laboratory for Laser Energetics, University of Rochester, Univ of Nevada - Reno, University of Nevada, Reno - Physics Department, Jilin University, China, Department of Physics, University of California, Berkeley, Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Advanced Materials Laboratory, National Institute for Materials Science, Department of Physics \& Astronomy, California State University, Long Beach, CA 90840, UC Santa Barbara, Department of Physics and Astronomy, University of California, Riverside, University of California at Merced, Laboratoire de Physique des Plasmas (CNRS/Ecole Polytechnique/UPMC/Universit\'e Paris Sud), Ecole Polytechnique, 91128 Palaiseau, France, University of Nevada, Reno, NV 89557, USA, University of Nevada, Reno, NV 89557 USA, University of Nevada-Reno